Biscarbazole derivative, material for organic electroluminescence device and organic electroluminescence device using the same

ABSTRACT

A biscarbazole derivative of the invention is represented by a formula (1) below. 
     
       
         
         
             
             
         
       
     
     In the formula (1): A 1  represents a substituted or unsubstituted nitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms; A 2  represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbon atoms, or substituted or unsubstituted nitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms; X 1  and X 2  each are a linking group; Y 1  to Y 4  each represent a substituent; p and q represent an integer of 1 to 4; and r and s represent an integer of 1 to 3.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Ser. No. 13/372,954 filedFeb. 14, 2012, which is a Continuation of U.S. Ser. No. 13/091,036,filed Apr. 20, 2011, which claims priority from Japanese PatentApplication No. 2010-097317, filed Apr. 20, 2010, Japanese PatentApplication No. 2010-291138, filed Dec. 27, 2010, U.S. ProvisionalApplication No. 61/353,047, filed Jun. 9, 2010, and U.S. ProvisionalApplication No. 61/433,084, filed Jan. 14, 2011, the entire contents ofwhich are expressly incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a biscarbazole derivative, a materialfor an organic electroluminescence device, and an organicelectroluminescence device using those.

2. Description of Related Art

A known organic electroluminescence device includes an organic thin-filmlayer between an anode and a cathode, the organic thin-film layerincluding an emitting layer, and emits light using exciton energygenerated by a recombination of holes and electrons injected into theemitting layer (see Patent Literature 1: WO2003-080760, PatentLiterature 2: Japanese Patent No.: 3139321, Patent Literature 3:Japanese Patent No.: 4357781, Patent Literature 4: JP-A-2003-151774,Patent Literature 5: JP-A-2008-135498, Patent Literature 6:JP-A-2009-21336, Patent Literature 7: JP-A-2008-214307).

Such an organic EL device, which has the advantages as a self-emittingdevice, is expected to serve as an emitting device excellent in luminousefficiency, image quality, power consumption and thin design.

In forming the emitting layer, a doping method, according to which anemitting material (dopant) is doped to a host, has been known as ausable method.

The emitting layer formed by the doping method can efficiently generateexcitons from electric charges injected into the host. With the excitonenergy generated by the excitons being transferred to the dopant, thedopant can emit light with high efficiency.

Recently, in order to improve performance of the organicelectroluminescence device (hereinafter, occasionally referred to as anorganic EL device), a doping method has been further studied to find asuitable host material.

Such a host material is disclosed in, for instance, Patent Literatures 1to 7. Patent Literatures 1 to 7 disclose a compound including acarbazole skeleton and a nitrogen-containing aromatic ring in the samemolecule and a compound including a plurality of carbazole skeletons inthe same molecule, as shown in the following compounds I to VIII.

The compounds I and II disclosed in Patent Literature 1 each have astructure in which a carbazole skeleton is bonded to a benzene ring andan electron-deficient nitrogen-containing hetero aromatic ringstructure. A carbazole skeleton, which is represented by polyvinylcarbazole, has been known as a main skeleton of a hole transportingmaterial. In contrast, the electron-deficient nitrogen-containing heteroaromatic ring structure has been known as a structure having a highelectron transporting capability. In other words, the compounds I and IIdisclosed in Patent Literature 1 are materials for balancing chargetransportation by combining a hole transporting skeleton and an electrontransporting skeleton.

The compound I has only a single carbazole skeleton and lacks a holetransporting capability, so that a favorable luminescence propertycannot be obtained. The compound II has two carbazolyl groups that arebranched to left and right relative to a bond axis of a pyrimidine ringand a benzene ring (two conjugated aromatic ring). Accordingly, anoverlapping margin of the carbazole skeleton between molecules isimpaired, so that a hole transporting capability is insufficient and are-bonding position of charges is likely to be closer to the anode.Consequently, favorable luminescence property and lifetime propertycannot be obtained.

In order to enlarge the overlapping margin between the molecules andexhibit a sufficient hole transporting capability, it has been proposedto incorporate a structure in which carbazole skeletons are linked inthe molecules. For instance, the compounds III to VI disclosed in PatentLiteratures 2 to 5 have a structure in which two carbazole skeletons arelinked. However, since none of the compounds III to VI has anelectron-deficient nitrogen-containing hetero aromatic ring structure,adjustment of carrier balance between holes and electrons is difficult,so that a favorable luminescence property cannot be obtained.

The compound VII disclosed in Patent Literature 6 has anelectron-deficient nitrogen-containing hetero aromatic ring structureand a carbazole-linking structure. However, two carbazole skeletons arebonded to a carbon atom at 3-position by a nitrogen atom. In thisstructure, the two carbazole skeletons are twisted to each other to loseflatness. Accordingly, the overlapping margin between the moleculesbecomes small and a hole transporting capability becomes insufficient,so that favorable luminescence property and lifetime property cannot beobtained.

The compound VIII disclosed in Patent Literature 7 has a structure inwhich a bipyridyl group (a nitrogen-containing aromatic heterocyclicgroup) is bonded to a benzene ring of a carbazole skeleton. The compoundis not disclosed as a phosphorescent host material although being usedas a material for an electron transporting layer. However, since thecompound is considered to exhibit a high electron transportingcapability, when used as a host material, the compound provides a poorcarrier balance within the emitting layer and fails to exhibit afavorable luminescence property.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide a novelbiscarbazole derivative having a hole transporting capability and anelectron transporting capability and exhibiting an excellent carrierbalance, a material for an organic EL device (hereinafter, referred toas an organic-EL-device material) and a phosphorescent and long-lifeorganic EL device using those.

After dedicated study to achieve the above object, the inventors foundthat a compound including two carbazolyl groups and anitrogen-containing heterocyclic group effectively works for optimizinga carrier balance in the emitting layer of an organic EL device, andachieved the invention.

Specifically, a biscarbazole derivative according to an aspect of theinvention is represented by a formula (1) below. Herein, “hydrogen” ismeant to also include deuterium.

In the formula (1): A¹ represents a substituted or unsubstitutednitrogen-containing heterocyclic group having 1 to 30 carbon atomsforming a ring (hereinafter, referred to as ring carbon atoms);

A² represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, or substituted or unsubstitutednitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms;

X¹ and X² each are a linking group and independently represent a singlebond, substituted or unsubstituted aromatic hydrocarbon group having 6to 30 ring carbon atoms, substituted or unsubstituted fused aromatichydrocarbon group having 6 to 30 ring carbon atoms, substituted orunsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms.

Y¹ to Y⁴ independently represent a hydrogen atom, fluorine atom, cyanogroup, substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, substituted or unsubstituted haloalkyl group having 1 to 20carbon atoms, substituted or unsubstituted haloalkoxy group having 1 to20 carbon atoms, substituted or unsubstituted alkylsilyl having 1 to 10carbon atoms, substituted or unsubstituted arylsilyl having 6 to 30carbon atoms, substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, substituted or unsubstituted fusedaromatic hydrocarbon group having 6 to 30 ring carbon atoms, substitutedor unsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms;

adjacent ones of Y¹ to Y⁴ may be bonded to each other to form a ringstructure;

p and q represent an integer of 1 to 4; r and s represent an integer of1 to 3; and

when p and q are an integer of 2 to 4 and r and s are an integer of 2 to3, a plurality of Y¹ to Y⁴ may be the same or different.

When Y¹ to Y⁴ are bonded to each other to form a ring structure, thering structure is exemplified by structures represented by the followingformulae.

The biscarbazole derivative according to the aspect of the invention ispreferably represented by a formula (2) below.

In the formula (2), A¹, A², X¹, X², Y¹ to Y⁴, p, q, r and s representthe same as A¹, A², X¹, X², Y¹ to Y⁴, p, q, r and s in the formula (1).

Moreover, in the biscarbazole derivative according to the above aspectof the invention, A¹ in the formula (1A) or (1B) is preferably selectedfrom the group consisting of a substituted or unsubstituted pyridinering, substituted or unsubstituted pyrimidine ring and substituted orunsubstituted triazine ring, more preferably selected from a substitutedor unsubstituted pyrimidine ring or substituted or unsubstitutedtriazine ring, particularly preferably a substituted or unsubstitutedpyrimidine ring.

The biscarbazole derivative according to the aspect of the invention ispreferably represented by a formula (3) below in the formula (2)

In the formula (3): A², X¹, Y¹ to Y⁴, p, q, r and s represent the sameas A², X¹, Y¹ to Y⁴, p, q, r and s of the formula (1); Y⁵ represent thesame as Y¹ to Y⁴ of the formula (1); t represents an integer from 1 to3; and when t is an integer of 2 to 3, a plurality of Y⁵ may be the sameor different.

Moreover, in the biscarbazole derivative according to the aspect of theinvention represented by the formula (1) or (2), A¹ is preferably asubstituted or unsubstituted quinazoline ring.

The organic-EL-device material according to another aspect of theinvention contains the above biscarbazole derivative.

The organic EL device according to still another aspect of the inventionincludes: a cathode; an anode; and a plurality of organic thin-filmlayers provided between the cathode and the anode, and the organicthin-film layer including an emitting layer, in which at least one layerof the organic thin-film layers contains the above-describedorganic-EL-device material.

In the organic EL device according to the above aspect of the invention,the emitting layer preferably contains the organic-EL-device materialaccording to the aspect of the invention as a host material.

Also preferably in the organic EL device according to the above aspectof the invention, the emitting layer includes a phosphorescent material.

The phosphorescent material is preferably an ortho-metalated complex ofa metal atom selected from iridium (Ir), osmium (Os) and platinum (Pt).

The organic EL device according to further aspect of the inventionincludes: a cathode; an anode; and a plurality of organic thin-filmlayers provided between a cathode and an anode, and the organicthin-film layer includes an emitting layer, in which at least one of theorganic thin-film layers is the emitting layer containing a first hostmaterial, a second host material and a phosphorescent material providingphosphorescence, the first host material being a compound represented bya formula (4) below.

In the formula (4): A¹ represents a substituted or unsubstitutednitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms;

-   -   A² represents a substituted or unsubstituted aromatic        hydrocarbon group having 6 to 30 ring carbon atoms, or        substituted or unsubstituted nitrogen-containing heterocyclic        group having 1 to 30 ring carbon atoms;

X¹ and X² each are a linking group and independently represent a singlebond, substituted or unsubstituted aromatic hydrocarbon group having 6to 30 ring carbon atoms, substituted or unsubstituted fused aromatichydrocarbon group having 6 to 30 ring carbon atoms, substituted orunsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms;

Y¹ to Y⁴ independently represent a hydrogen atom, fluorine atom, cyanogroup, substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, substituted or unsubstituted haloalkyl group having 1 to 20carbon atoms, substituted or unsubstituted haloalkoxy group having 1 to20 carbon atoms, substituted or unsubstituted alkylsilyl having 1 to 10carbon atoms, substituted or unsubstituted arylsilyl having 6 to 30carbon atoms, substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, substituted or unsubstituted fusedaromatic hydrocarbon group having 6 to 30 ring carbon atoms, substitutedor unsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms;

adjacent ones of Y¹ to Y⁴ may be bonded to each other to form a ringstructure;

p and q represent an integer of 1 to 4; r and s represent an integer of1 to 3; and

when p and q are an integer of 2 to 4 and r and s are an integer of 2 to3, a plurality of Y¹ to Y⁴ may be the same or different.

When Y¹ to Y⁴ are bonded to each other to form a ring structure, thering structure is exemplified by the same structures as ones listed whenY¹ to Y⁴ are bonded to each other to form a ring structure in theformula (1).

In the organic EL device according to the above aspect of the invention,the second host material is preferably represented by either one of aformula (5) or (6) below.

(Cz⁻)_(a)A³  (5)

Cz(⁻A³)_(b)  (6)

In the formula (5) or (6): Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylaryl group;

A³ represents a group represented by a formula (7A) or (7B) below; and

a and b each represent an integer of 1 to 3.

(M¹)_(c)−(L⁵)_(d)−(M²)_(e)  (7A)

In the formula (7A): M¹ and M² each independently represent asubstituted or unsubstituted nitrogen-containing aromatic heterocyclicring or nitrogen-containing fused aromatic heterocyclic ring having 2 to40 ring carbon atoms; M¹ and M² may be the same or different;

L⁵ represents a single bond, substituted or unsubstituted aromatichydrocarbon group having 6 to 30 carbon atoms, substituted orunsubstituted fused aromatic hydrocarbon group having 6 to 30 carbonatoms, substituted or unsubstituted cycloalkylene group having 5 to 30carbon atoms, substituted or unsubstituted aromatic heterocyclic grouphaving 2 to 30 carbon atoms, or substituted or unsubstituted fusedaromatic heterocyclic group having 2 to 30 carbon atoms;

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

(M³)_(c)−(L⁶)_(d)−(M⁴)_(e)  (7B)

In the formula (7B): M³ and M⁴ each independently represent asubstituted or unsubstituted aromatic hydrocarbon group having 6 to 40ring carbon atoms; M³ and M⁴ may be the same or different;

L⁶ represents a single bond, substituted or unsubstituted aromatichydrocarbon group having 6 to 30 carbon atoms, substituted orunsubstituted fused aromatic hydrocarbon group having 6 to 30 carbonatoms, or substituted or unsubstituted cycloalkylene group having 5 to30 carbon atoms;

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

In the organic EL device according to the above aspect of the invention,the second host material is preferably represented by a formula (8)below.

In the formula (8): R¹⁰¹ to R¹⁰⁶ each independently represent a hydrogenatom, halogen atom, substituted or unsubstituted alkyl group having 1 to40 carbon atoms, substituted or unsubstituted cycloalkyl group having 3to 15 carbon atoms, substituted or unsubstituted heterocyclic grouphaving 3 to 20 carbon atoms, substituted or unsubstituted alkoxy grouphaving 1 to 40 carbon atoms, substituted or unsubstituted aryl grouphaving 6 to 40 carbon atoms, substituted or unsubstituted aryloxy grouphaving 6 to 20 carbon atoms, substituted or unsubstituted aralkyl grouphaving 7 to 20 carbon atoms, substituted or unsubstituted arylaminogroup having 6 to 40 carbon atoms, substituted or unsubstitutedalkylamino group having 1 to 40 carbon atoms, substituted orunsubstituted aralkylamino group having 7 to 60 carbon atoms,substituted or unsubstituted arylcarbonyl group having 7 to 40 carbonatoms, substituted or unsubstituted arylthio group having 6 to 20 carbonatoms, substituted or unsubstituted halogenated alkyl group having 1 to40 carbon atoms or cyano group;

at least one of R¹⁰¹ to R¹⁰⁶ is a substituted or unsubstituted9-carbazolyl group, substituted or unsubstituted azacarbazolyl grouphaving 2 to 5 nitrogen atoms, or -L-9-carbazolyl group;

L represents a substituted or unsubstituted alkyl group having 1 to 40carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to15 carbon atoms, substituted or unsubstituted heterocyclic group having3 to 20 carbon atoms, substituted or unsubstituted alkoxy group having 1to 40 carbon atoms, substituted or unsubstituted aryl group having 6 to40 carbon atoms, substituted or unsubstituted aryloxy group having 6 to20 carbon atoms, substituted or unsubstituted aralkyl group having 7 to20 carbon atoms, substituted or unsubstituted arylamino group having 6to 40 carbon atoms, substituted or unsubstituted alkylamino group having1 to 40 carbon atoms, substituted or unsubstituted aralkylamino grouphaving 7 to 60 carbon atoms, substituted or unsubstituted arylcarbonylgroup having 7 to 40 carbon atoms, substituted or unsubstituted arylthiogroup having 6 to 20 carbon atoms, or substituted or unsubstitutedhalogenated alkyl group having 1 to 40 carbon atoms;

Xa represents a sulfur atom, oxygen atom or N—R¹⁰⁸; and

R¹⁰⁸ represents the same as R¹⁰¹ to R¹⁰⁶.

In the organic EL device according to the aspect of the invention, thesecond host material is preferably a compound selected from the groupconsisting of polycyclic aromatic compounds represented by formulae(9A), (9B) and (9C) below.

Ra—Ar¹⁰¹—Rb  (9A)

Ra—Ar¹⁰¹—Ar¹⁰²—Rb  (9B)

Ra—Ar¹⁰¹—Ar¹⁰²—Ar¹⁰³—Rb  (9C)

In the formulae (9A) to (9C): Ar¹⁰¹, Ar¹⁰², Ar¹⁰³, Ra and Rb represent apolycyclic aromatic skeleton having 6 to 60 ring carbon atoms selectedfrom a substituted or unsubstituted benzene ring, substituted orunsubstituted naphthalene ring, substituted or unsubstituted chrysenering, substituted or unsubstituted fluoranthene ring, substituted orunsubstituted phenanthrene ring, substituted or unsubstitutedbenzophenanthrene ring, substituted or unsubstituted dibenzophenanthrenering, substituted or unsubstituted triphenylene ring, substituted orunsubstituted benzo[a]triphenylene ring, substituted or unsubstitutedbenzochrysene ring, substituted or unsubstituted benzo[b]fluoranthenering, substituted or unsubstituted fluorene ring and substituted orunsubstituted picene ring.

Moreover, in the organic EL device according to the aspect of theinvention, in the formulae (9A) to (9C), either one or both of Ra and Rbare preferably selected from the group consisting of a substituted orunsubstituted phenanthrene ring, substituted or unsubstitutedbenzo[c]phenanthrene ring and substituted or unsubstituted fluoranthenering.

In the organic EL device according to the above aspect of the invention,the second host material is preferably a monoamine derivativerepresented by any one of formulae (10) to (12) below.

Ar¹¹¹, Ar¹¹² and Ar¹¹³ are a substituted or unsubstituted aryl group orheteroaryl group.

Ar¹¹⁴, Ar¹¹⁵ and Ar¹¹⁷ are a substituted or unsubstituted aryl group orheteroaryl group.

Ar¹¹⁶ is a substituted or unsubstituted arylene group or heteroarylenegroup.

Ar¹¹⁸, Ar¹¹⁹ and Ar¹²¹ are a substituted or unsubstituted aryl group orheteroaryl group.

Ar¹²⁰ is a substituted or unsubstituted arylene group or heteroarylenegroup.

n is an integer of 2 to 5: when n is 2 or more, Ar¹²⁰ may be the same ordifferent.

In the organic EL device according to the aspect of the invention, thesecond host material is represented by a formula (13) or (14) below.

In the formula (14): X³ represents a substituted or unsubstitutedarylene group having 10 to 40 ring carbon atoms; and A³ to A⁶ representa substituted or unsubstituted aryl group having 6 to 60 ring carbonatoms, or heteroaryl group having 6 to 60 ring atoms.

In the formula (14), A⁷ to A⁹ represent a substituted or unsubstitutedaryl group having 6 to 60 ring carbon atoms, or heteroaryl group having6 to 60 ring atoms.

In the organic EL device according to the above aspect of the invention,the second host material is more preferably represented by any one offormulae (15) to (19) below.

In the formulae (15) to (19): A¹⁰ to A¹⁹ each represent a substituted orunsubstituted aryl group having 6 to 40 carbon atoms, substituted orunsubstituted aromatic heterocyclic group having 2 to 40 carbon atoms,substituted or unsubstituted aryl group having 8 to 40 carbon atomsbonded with an aromatic amino group, or substituted or unsubstitutedaryl group having 8 to 40 carbon atoms bonded with an aromaticheterocyclic group;

A¹⁰, A¹³, A¹⁵ and A¹⁷ are adapted to be respectively bonded to A¹¹, A¹⁴,A¹⁶ and A¹⁸ to form a ring;

X⁴ to X⁹ represent a single bond or a linking group having 1 to 30carbon atoms;

Y⁶ to Y²⁴ represent a hydrogen atom, halogen atom, substituted orunsubstituted alkyl group having 1 to 40 carbon atoms, substituted orunsubstituted heterocyclic group having 3 to 20 carbon atoms,substituted or unsubstituted aryl group having 6 to 40 carbon atoms,substituted or unsubstituted aralkyl group having 7 to 20 carbon atoms,substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms,substituted or unsubstituted alkylamino group having 1 to 40 carbonatoms, substituted or unsubstituted aralkylamino group having 7 to 60carbon atoms, substituted or unsubstituted alkylsilyl group having 3 to20 carbon atoms, substituted or unsubstituted arylsilyl group having 8to 40 carbon atoms, substituted or unsubstituted aralkylsilyl grouphaving 8 to 40 carbon atoms, or substituted or unsubstituted halogenatedalkyl group having 1 to 40 carbon atoms; and

X_(A), X_(B), X_(C), X_(D), X_(E) each represent a sulfur atom, anoxygen atom or a monoaryl-substituted nitrogen atom.

In the organic EL device according to the above aspect of the invention,it is preferable that the emitting layer includes a host material and aphosphorescent material, the phosphorescent material being anortho-metalated complex of a metal atom selected from iridium (Ir),osmium (Os) and platinum (Pt).

In the organic EL device according to the above aspect of the invention,it is preferable that an electron injecting layer is provided betweenthe cathode and the emitting layer and includes a nitrogen-containingcyclic derivative.

In the organic EL device according to the above aspect of the invention,it is preferable that an electron transporting layer is provided betweenthe cathode and the emitting layer and includes the above-describedorganic-EL-device material.

In the organic EL device according to the above aspect of the invention,it is preferable that a reduction-causing dopant is present at aninterfacial region between the cathode and the organic thin-film layer.

The organic EL device according to the above aspect of the inventionpreferably includes a cathode, an anode, and an organic layer betweenthe cathode and the anode, in which the organic layer include thebiscarbazole derivative represented by the formulae (1) to (3).

In the organic electroluminescence device according to the above aspectof the invention, the organic layer preferably includes a phosphorescentmaterial, the phosphorescent material being an ortho-metalated complexof a metal atom selected from iridium (Ir), osmium (Os) and platinum(Pt).

According to the above aspect of the invention, since the biscarbazolederivative is used as the organic-EL-device material, a long-lifeorganic electroluminescence device can be provided. Moreover, theorganic-EL-device material is effective as organic-electron-devicematerial for an organic solar cell, an organic semiconductor laser, asensor using an organic substance and an organic TFT.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows an exemplary arrangement of an organicelectroluminescence device according to an exemplary embodiment of theinvention.

FIG. 2A shows an energy diagram of an emitting layer in an organic ELdevice according to Examples of the invention.

FIG. 2B shows an energy diagram of an emitting layer in an organic ELdevice according to Examples of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

The invention will be described below in detail.

First Exemplary Embodiment Arrangement of Organic EL Device

First of all, arrangement(s) of an organic EL device will be describedbelow.

The followings are representative arrangement examples of an organic ELdevice:

(1) anode/emitting layer/cathode;(2) anode/hole injecting layer/emitting layer/cathode;(3) anode/emitting layer/electron injecting•transporting layer/cathode;(4) anode/hole injecting layer/emitting layer/electroninjecting•transporting layer/cathode;(5) anode/organic semiconductor layer/emitting layer/cathode;(6) anode/organic semiconductor layer/electron blocking layer/emittinglayer/cathode;(7) anode/organic semiconductor layer/emitting layer/adhesion improvinglayer/cathode;(8) anode/hole injecting•transporting layer/emitting layer/electroninjecting•transporting layer/cathode;(9) anode/insulating layer/emitting layer/insulating layer/cathode;(10) anode/inorganic semiconductor layer/insulating layer/emittinglayer/insulating layer/cathode;(11) anode/organic semiconductor layer/insulating layer/emittinglayer/insulating layer/cathode;(12) anode/insulating layer/hole injecting•transporting layer/emittinglayer/insulating layer/cathode; and(13) anode/insulating layer/hole injecting•transporting layer/emittinglayer/electron injecting•transporting layer/cathode.

While the arrangement (8) is preferably used among the above, thearrangement of the invention is not limited to the above arrangements.

FIG. 1 schematically shows an exemplary arrangement of an organic ELdevice according to a first exemplary embodiment of the invention.

The organic EL device 1 includes a transparent substrate 2, an anode 3,a cathode 4 and an organic thin-film layer 10 positioned between theanode 3 and the cathode 4.

The organic thin-film layer 10 includes a phosphorescent-emitting layer5 containing a phosphorescent host (a host material) and aphosphorescent dopant (a phosphorescent material). A layer such as ahole injecting/transporting layer 6 may be provided between thephosphorescent-emitting layer 5 and the anode 3 while a layer such as anelectron injecting/transporting layer 7 may be provided between thephosphorescent-emitting layer 5 and the cathode 4.

In addition, an electron blocking layer may be provided to thephosphorescent-emitting layer 5 adjacent to the anode 3 while a holeblocking layer may be provided to the phosphorescent-emitting layer 5adjacent to the cathode 4.

With this arrangement, electrons and holes can be trapped in thephosphorescent-emitting layer 5, thereby enhancing probability ofexciton generation in the phosphorescent-emitting layer 5.

It should be noted that a “fluorescent host” and a “phosphorescent host”herein respectively mean a host combined with a fluorescent dopant and ahost combined with a phosphorescent dopant, and that a distinctionbetween the fluorescent host and phosphorescent host is notunambiguously derived only from a molecular structure of the host in alimited manner.

In other words, the fluorescent host herein means a material for forminga fluorescent-emitting layer containing a fluorescent dopant, and doesnot mean a host that is only usable as a host of a fluorescent material.

Likewise, the phosphorescent host herein means a material for forming aphosphorescent-emitting layer containing a phosphorescent dopant, anddoes not mean a host that is only usable as a host of a phosphorescentmaterial.

It should be noted that the “hole injecting/transporting layer” hereinmeans “at least either one of a hole injecting layer and a holetransporting layer” while the “electron injecting/transporting layer”herein means “at least either one of an electron injecting layer and anelectron transporting layer.”

Transparent Substrate

The organic EL device according to this exemplary embodiment is formedon a light-transmissive substrate. The light-transmissive plate, whichsupports the organic EL device, is preferably a smoothly-shapedsubstrate that transmits 50% or more of light in a visible region of 400nm to 700 nm.

Specifically, a glass plate, a polymer plate, and the like arepreferable.

For the glass plate, materials such as soda-lime glass,barium/strontium-containing glass, lead glass, aluminosilicate glass,borosilicate glass, barium borosilicate glass and quartz can be used.

For the polymer plate, materials such as polycarbonate, acryl,polyethylene terephthalate, polyether sulfide and polysulfone can beused.

Anode and Cathode

The anode of the organic EL device is used for injecting holes into thehole injecting layer, the hole transporting layer or the emitting layer.It is effective that the anode has a work function of 4.5 eV or more.

Exemplary materials for the anode are alloys of indium-tin oxide (ITO),tin oxide (NESA), indium zinc oxide, gold, silver, platinum and copper.

The anode may be made by forming a thin film from these electrodematerials through methods such as vapor deposition and sputtering.

When light from the emitting layer is to be emitted through the anode asin this embodiment, the anode preferably transmits more than 10% of thelight in the visible region. Sheet resistance of the anode is preferablyseveral hundreds Ω/square or lower. Although depending on the materialof the anode, thickness of the anode is typically in a range of 10 nm to1 μm, and preferably in a range of 10 to 200 nm.

The cathode is preferably formed of a material with smaller workfunction in order to inject electrons into the electron injecting layer,the electron transporting layer and the emitting layer.

Although a material for the cathode is subject to no specificlimitation, examples of the material are indium, aluminum, magnesium,alloy of magnesium and indium, alloy of magnesium and aluminum, alloy ofaluminum and lithium, alloy of aluminum, scandium and lithium, alloy ofmagnesium and silver and the like.

Like the anode, the cathode may be made by forming a thin film from theabove materials through a method such as vapor deposition or sputtering.In addition, the light may be emitted through the cathode.

Emitting Layer

The emitting layer of the organic EL device is an organic thin-filmlayer having a function for providing conditions for recombination ofthe electrons and the holes to emit light.

Injectability of the holes may differ from that of the electrons andtransporting capabilities of the hole and the electrons (represented bymobilities of the holes and the electrons) may differ from each other.

As a method of forming the emitting layer, known methods such as vapordeposition, spin coating and an LB method may be employed.

The emitting layer is preferably a molecular deposit film.

The molecular deposit film means a thin film formed by depositing amaterial compound in gas phase or a film formed by solidifying amaterial compound in a solution state or in liquid phase. The moleculardeposit film is typically distinguished from a thin film formed by theLB method (molecular accumulation film) by differences in aggregationstructures, higher order structures and functional differences arisingtherefrom.

As disclosed in JP-A-57-51781, the emitting layer can be formed from athin film formed by spin coating or the like, the thin film being formedfrom a solution prepared by dissolving a binder (e.g. a resin) and amaterial compound in a solvent.

An organic EL device according to this exemplary embodiment includes: acathode; an anode; and a single or a plurality of organic thin-filmlayers provided between the cathode and the anode, in which the organicthin-film layer(s) includes at least one emitting layer, and at leastone of the organic thin-film layers includes at least one phosphorescentmaterial and, as an organic-EL-device material, at least onebiscarbazole derivative according to this exemplary embodiment(described later). It is also preferable that at least one emittinglayer includes the biscarbazole derivative as the organic-EL-devicematerial according to this exemplary embodiment and at least onephosphorescent material.

Biscarbazole Derivative

The biscarbazole derivative according to this exemplary embodiment isrepresented by a formula (1) below.

In the formula (1): A¹ represents a substituted or unsubstitutednitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms;

A² represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, or substituted or unsubstitutednitrogen-containing heterocyclic group having 1 to 30 ring carbon atoms;

X¹ and X² each are a linking group and independently represent a singlebond, substituted or unsubstituted aromatic hydrocarbon group having 6to 30 ring carbon atoms, substituted or unsubstituted fused aromatichydrocarbon group having 6 to 30 ring carbon atoms, substituted orunsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms;

Y¹ to Y⁴ independently represent a hydrogen atom, fluorine atom, cyanogroup, substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, substituted or unsubstituted haloalkyl group having 1 to 20carbon atoms, substituted or unsubstituted haloalkoxy group having 1 to20 carbon atoms, substituted or unsubstituted alkylsilyl having 1 to 10carbon atoms, substituted or unsubstituted arylsilyl having 6 to 30carbon atoms, substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, substituted or unsubstituted fusedaromatic hydrocarbon group having 6 to 30 ring carbon atoms, substitutedor unsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms;

adjacent ones of Y¹ to Y⁴ may be bonded to each other to form a ringstructure;

p and q represent an integer of 1 to 4; r and s represent an integer of1 to 3; and

when p and q are an integer of 2 to 4 and r and s are an integer of 2 to3, a plurality of Y¹ to Y⁴ may be the same or different.

When Y¹ to Y⁴ are bonded to each other to form a ring structure, thering structure is exemplified by structures represented by the followingformulae.

The biscarbazole derivative represented by the formula (1) is morepreferably represented by a formula (2) below.

In the formula (2), A¹, A², X¹, X², Y¹ to Y⁴, p, q, r and s are the sameas those in the formula (1).

In the formula (2), A¹ and A² are preferably a nitrogen-containingheterocyclic group at the same time. More preferably, A¹ and A² are asubstituted or unsubstituted aromatic heterocyclic group having 2 to 30ring carbon atoms, or substituted or unsubstituted fused aromaticheterocyclic group having 2 to 30 ring carbon atoms.

Moreover, A¹ in the formula (2) is preferably selected from the groupconsisting of a substituted or unsubstituted pyridine ring, substitutedor unsubstituted pyrimidine ring and substituted or unsubstitutedtriazine ring, more preferably selected from a substituted orunsubstituted pyrimidine ring or substituted or unsubstituted triazinering.

A¹ in the formula (2) is further preferably a substituted orunsubstituted pyrimidine ring and is particularly preferably representedby a formula (3) below.

In the formula (3), A², X¹, Y¹ to Y⁴, p, q, r and s are the same asthose in the formula (1); Y⁵ represents the same as Y¹ to Y⁴ of theformula (1); t represents an integer from 1 to 3; and when t is aninteger of 2 to 3, a plurality of Y⁵ may be the same or different.

In the formula (3), A² is preferably a nitrogen-containing heterocyclicgroup. More preferably, A² is a substituted or unsubstituted aromaticheterocyclic group having 2 to 30 ring carbon atoms, or substituted orunsubstituted fused aromatic heterocyclic group having 2 to 30 ringcarbon atoms.

In the formula (1) or (2), A¹ is preferably a substituted orunsubstituted quinazoline ring.

In the formulae (1) to (3), X¹ is preferably a single bond or asubstituted or unsubstituted divalent aromatic hydrocarbon group having6 to 30 ring carbon atoms, more preferably a substituted orunsubstituted divalent aromatic hydrocarbon group having 6 to 30 ringcarbon atoms, particularly preferably a benzene ring or naphthalenering.

When X¹ is a substituted or unsubstituted benzene ring in the formulae(1) to (3), A¹ and the carbazolyl group, which are bonded to X¹, arepreferably in meta positions or para positions. Particularly preferably,X¹ is unsubstituted para-phenylene.

In the formulae (1) and (2), the pyridine ring, pyrimidine ring andtriazine ring are more preferably represented by the following formulae.In the formulae, Y and Y′ represent a substituent. Examples of thesubstituent are the same groups as those represented by Y¹ to Y⁴ asdescribed above. Y and Y′ may be the same or different. Preferredexamples thereof are the substituted or unsubstituted aromatichydrocarbon group or fused aromatic hydrocarbon group having 6 to 30ring carbon atoms, and the substituted or unsubstituted aromaticheterocyclic group or fused aromatic heterocyclic group having 2 to 30ring carbon atoms. In the following formulae, * represents a bondingposition to X¹ or X².

In the formulae (1) and (2), the quinazoline ring is represented by thefollowing formula. Y represents a substituent. u represents an integerof 1 to 5. When u is an integer of 2 to 5, a plurality of Y may be thesame or different. As the substituent Y, the same groups as those forthe above Y¹ to Y⁴ are usable, among which preferred examples thereofare the substituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 30 ring carbon atoms, and thesubstituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 30 ring carbon atoms. Also inthe following formulae, * represents a bonding position to X¹ or X².

In the formulae (1) to (3), the alkyl group, alkoxy group, haloalkylgroup, haloalkoxy group and alkylsilyl group, which are represented byY¹ to Y⁵, may be linear, branched or cyclic.

In the formulae (1) to (3), examples of the alkyl group having 1 to 20carbon atoms are a methyl group, ethyl group, propyl group, isopropylgroup, n-butyl group, s-butyl group, isobutyl group, t-butyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonylgroup, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecylgroup, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group,n-heptadecyl group, n-octadecyl group, neo-pentyl group, 1-methylpentylgroup, 2-methylpentyl group, 1-pentylhexyl group, 1-butylpentyl group,1-heptyloctyl group, 3-methylpentyl group, cyclopentyl group, cyclohexylgroup, cycloheptyl group, cyclooctyl group and 3,5-tetramethylcyclohexylgroup. Examples of the alkyl group having 1 to 10 carbon atoms are amethyl group, ethyl group, propyl group, isopropyl group, n-butyl group,s-butyl group, isobutyl group, t-butyl group, cyclopentyl group,cyclohexyl group and cycloheptyl group.

As the alkoxy group having 1 to 20 carbon atoms, an alkoxy group having1 to 6 carbon atoms is preferable and specific examples thereof are amethoxy group, ethoxy group, propoxy group, butoxy group, pentyloxygroup, and hexyloxy group.

The haloalkyl group having 1 to 20 carbon atoms is exemplified by anhaloalkyl group provided by substituting the alkyl group having 1 to 20carbon atoms with one or more halogen atoms. Preferred one of thehalogen atoms is fluorine. The haloalkyl group is exemplified by atrifluoromethyl group and a 2,2,2-trifluoroethyl group.

The haloalkoxy group having 1 to 20 carbon atoms is exemplified by ahaloalkoxy group provided by substituting the alkoxy group having 1 to20 carbon atoms with one or more halogen atoms.

Examples of the alkylsilyl group having 1 to 10 carbon atoms are atrimethylsilyl group, triethylsilyl group, tributylsilyl group,dimethylethylsilyl group, dimethylisopropylsilyl group,dimethylpropylsilyl group, dimethylbutylsilyl group,dimethyl-tertiary-butylsilyl group and diethylisopropylsilyl group.

Examples of the arylsilyl group having 6 to 30 carbon atoms are aphenyldimethylsilyl group, diphenylmethylsilyl group,diphenyl-tertiary-butylsilyl group and triphenylsilyl group.

Examples of the aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 30 ring carbon atoms are a pyroryl group,pyrazinyl group, pyridinyl group, indolyl group, isoindolyl group, furylgroup, benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group,dibenzothiophenyl group, quinolyl group, isoquinolyl group, quinoxalinylgroup, carbazolyl group, phenantridinyl group, acridinyl group,phenanthrolinyl group, thienyl group and a group formed from a pyridinering, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring,indol ring, quinoline ring, acridine ring, pirrolidine ring, dioxanering, piperidine ring, morpholine ring, piperadine ring, carbazole ring,furan ring, thiophene ring, oxazole ring, oxadiazole ring, benzooxazolering, thiazole ring, thiadiazole ring, benzothiazole ring, triazolering, imidazole ring, benzoimidazole ring, pyrane ring and dibenzofuranring. Among the above, the aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 10 ring carbon atoms is preferable.

Examples of the aromatic hydrocarbon group or fused aromatic hydrocarbongroup having 6 to 30 ring carbon atoms are a phenyl group, naphthylgroup, phenanthryl group, biphenyl group, terphenyl group, quarterphenylgroup, fluoranthenyl group, triphenylenyl group, phenanthrenyl group,pyrenyl group, chrysenyl group, fluorenyl group, and9,9-dimethylfluorenyl group. Among the above, the aromatic hydrocarbongroup or fused aromatic hydrocarbon group having 6 to 20 ring carbonatoms is preferable.

When A¹, A², X¹, X² and Y¹ to Y⁵ of the formulae (1) to (3) each haveone or more substituents, the substituents are preferably a linear,branched or cyclic alkyl group having 1 to 20 carbon atoms; linear,branched or cyclic alkoxy group having 1 to 20 carbon atoms; linear,branched or cyclic haloalkyl group having 1 to 20 carbon atoms; linear,branched or cyclic alkylsilyl group having 1 to 10 carbon atoms;arylsilyl group having 6 to 30 ring carbon atoms; cyano group; halogenatom; aromatic hydrocarbon group or fused aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms; or aromatic heterocyclic group orfused aromatic heterocyclic group having 2 to 30 ring carbon atoms.

Examples of the linear, branched or cyclic alkyl group having 1 to 20carbon atoms; linear, branched or cyclic alkoxy group having 1 to 20carbon atoms; linear, branched or cyclic haloalkyl group having 1 to 20carbon atoms; linear, branched or cyclic alkylsilyl group having 1 to 10carbon atoms; arylsilyl group having 6 to 30 ring carbon atoms; aromatichydrocarbon group or fused aromatic hydrocarbon group having 6 to 30ring carbon atoms; and aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 30 ring carbon atoms are theabove-described groups. The halogen atom is exemplified by a fluorineatom.

Examples of compounds for the biscarbazole derivative according to thisexemplary embodiment represented by the formulae (1) to (3) are asfollows.

An organic-EL-device material according to this exemplary embodimentcontains the above biscarbazole derivative.

The organic-EL-device material according to this exemplary embodimentincludes the biscarbazole derivative represented by any one of the aboveformulae (1) to (3).

The organic EL device according to this exemplary embodiment includes acathode, an anode, and an organic layer between the cathode and theanode, in which the organic layer include the biscarbazole derivativeany one of the above formulae (1) to (3).

In the organic EL device according to this exemplary embodiment, theemitting layer may preferably contain the organic-EL-device materialaccording to this exemplary embodiment.

The organic EL device according to this exemplary embodiment maypreferably contain the electron injecting/transporting layer, in whichthe electron injecting/transporting layer may preferably contain theorganic-EL-device material according to this exemplary embodiment.

The organic EL device according to this exemplary embodiment maypreferably contain at least one of the electron injecting/transportinglayer and the hole blocking layer that contains the organic-EL-devicematerial according to this exemplary embodiment.

The organic EL device according to this exemplary embodiment maypreferably include the hole transporting layer (hole injecting layer)that contains the organic-EL-device material according to this exemplaryembodiment.

Phosphorescent Material

According to this exemplary embodiment, the phosphorescent materialpreferably contains a metal complex, and the metal complex preferablyhas a metal atom selected from Ir, Pt, Os, Au, Cu, Re and Ru, and aligand. Particularly, the ligand preferably has an ortho-metal bond.

The phosphorescent material is preferably a compound containing a metalselected from iridium (Ir), osmium (Os) and platinum (Pt) because such acompound, which exhibits high phosphorescence quantum yield, can furtherenhance external quantum efficiency of the emitting device. Thephosphorescent material is more preferably a metal complex such as aniridium complex, osmium complex or platinum complex, among which aniridium complex and platinum complex are more preferable and orthometalation of an iridium complex is the most preferable.

Examples of such a preferable metal complex are shown below.

According to this exemplary embodiment, at least one of thephosphorescent material contained in the emitting layer preferably emitslight with the maximum wavelength of 450 nm to 720 nm.

By doping the phosphorescent material (phosphorescent dopant) havingsuch an emission wavelength to the specific host material used in thisexemplary embodiment so as to form the emitting layer, the organic ELdevice can exhibit high efficiency.

Reduction-Causing Dopant

In the organic EL device according to this exemplary embodiment, areduction-causing dopant may be preferably contained in an interfacialregion between the cathode and the organic thin-film layer.

With this arrangement, the organic EL device can emit light withenhanced luminance intensity and have a longer lifetime.

The reduction-causing dopant may be at least one compound selected froman alkali metal, alkali metal complex, alkali metal compound, alkaliearth metal, alkali earth metal complex, alkali earth metal compound,rare-earth metal, rare-earth metal complex, rare-earth metal compoundand the like.

Examples of the alkali metal are Na (work function: 2.36 eV), K (workfunction: 2.28 eV), Rb (work function: 2.16 eV), Cs (work function: 1.95eV) and the like, among which a substance having a work function of 2.9eV or less is particularly preferable. Among the above, thereduction-causing dopant is preferably K, Rb or Cs, more preferably Rbor Cs, the most preferably Cs.

Examples of the alkali earth metal are Ca (work function: 2.9 eV), Sr(work function: 2.0 to 2.5 eV), Ba (work function: 2.52 eV) and thelike, among which a substance having a work function of 2.9 eV or lessis particularly preferable.

Examples of the rare-earth metal are Sc, Y, Ce, Tb, Yb and the like,among which a substance having a work function of 2.9 eV or less isparticularly preferable.

Since the above preferable metals have particularly high reducibility,addition of a relatively small amount of the metals to an electroninjecting zone can enhance luminance intensity and lifetime of theorganic EL device.

Examples of the alkali metal compound include an alkali oxide such asLi₂O, Cs₂O and K₂O, and an alkali halide such as LiF, NaF, CsF and KF.LiF, Li₂O, and NaF are preferable.

Examples of the alkali earth metal compound include BaO, SrO, CaO andtheir mixture such as Ba_(x)Sr_(1-x)O (0<x<1) and Ba_(x)Ca_(1-x)O(0<x<1). BaO, SrO, and CaO are preferable.

Examples of the rare earth metal compound include YbF₃, ScF₃, ScO₃,Y₂O₃, Ce₂O₃, GdF₃ and TbF₃. YbF₃, ScF₃, and TbF₃ are preferable.

The alkali metal complex, alkali earth metal complex and rare earthmetal complex are not specifically limited as long as they contain atleast one metal ion of an alkali metal ion, an alkali earth metal ionand a rare earth metal ion. A ligand for each of the complexes ispreferably quinolinol, benzoquinolinol, acridinol, phenanthridinol,hydroxyphenyl oxazole, hydroxyphenyl thiazole, hydroxydiaryl oxadiazole,hydroxydiaryl thiadiazole, hydroxyphenyl pyridine, hydroxyphenylbenzoimidazole, hydroxybenzo triazole, hydroxy fluborane, bipyridyl,phenanthroline, phthalocyanine, porphyrin, cyclopentadiene, β-diketones,azomethines, or a derivative thereof, but the ligand is not limitedthereto.

The reduction-causing dopant is added to preferably form a layer or anisland pattern in the interfacial region. The layer of thereduction-causing dopant or the island pattern of the reduction-causingdopant is preferably formed by depositing the reduction-causing dopantby resistance heating deposition while an emitting material for formingthe interfacial region or an organic substance as an electron-injectingmaterial are simultaneously deposited, so that the reduction-causingdopant is dispersed in the organic substance. Dispersion concentrationat which the reduction-causing dopant is dispersed in the organicsubstance is a mole ratio (organic substance to reduction-causingdopant) of 100:1 to 1:100, preferably 5:1 to 1:5.

When the reduction-causing dopant forms the layer, the emitting materialor the electron injecting material for forming the organic layer of theinterfacial region is initially layered, and the reduction-causingdopant is subsequently deposited singularly thereon by resistanceheating deposition to form a preferably 0.1 to 15 nm-thick layer.

When the reduction-causing dopant forms the island pattern, the emittingmaterial or the electron injecting material for forming the organiclayer of the interfacial region is initially formed in an island shape,and the reduction-causing dopant is subsequently deposited singularlythereon by resistance heating deposition to form a preferably 0.05 to 1nm-thick island shape.

A ratio of the main component to the reduction-causing dopant in theorganic EL device according to this exemplary embodiment is preferably amole ratio (main component to reduction-causing dopant) of 5:1 to 1:5,more preferably 2:1 to 1:2.

Electron Injecting Layer and Electron Transporting Layer

The electron injecting layer or the electron transporting layer, whichaids injection of the electrons into the emitting layer, has a largeelectron mobility. The electron injecting layer is provided foradjusting energy level, by which, for instance, sudden changes of theenergy level can be reduced.

The organic EL device according to this exemplary embodiment preferablyincludes the electron injecting layer between the emitting layer and thecathode, and the electron injecting layer preferably contains anitrogen-containing cyclic derivative as the main component. Theelectron injecting layer may serve as the electron transporting layer.

It should be noted that “as the main component” means that thenitrogen-containing cyclic derivative is contained in the electroninjecting layer at a content of 50 mass % or more.

A preferable example of an electron transporting material for formingthe electron injecting layer is an aromatic heterocyclic compound havingin the molecule at least one heteroatom. Particularly, anitrogen-containing cyclic derivative is preferable. Thenitrogen-containing cyclic derivative is preferably an aromatic ringhaving a nitrogen-containing six-membered or five-membered ringskeleton, or a fused aromatic cyclic compound having anitrogen-containing six-membered or five-membered ring skeleton.

A preferable example of the nitrogen-containing cyclic derivative is anitrogen-containing cyclic metal chelate complex represented by thefollowing formula (A).

R² to R⁷ in the formula (A) each independently represent a hydrogenatom, a halogen atom, an oxy group, an amino group, a hydrocarbon grouphaving 1 to 40 carbon atoms, an alkoxy group, an aryloxy group, analkoxycarbonyl group, or an aromatic heterocyclic group. These groupsmay be substituted or unsubstituted.

Examples of the halogen atom include fluorine, chlorine, bromine, andiodine. In addition, examples of the substituted or unsubstituted aminogroup include an alkylamino group, an arylamino group, and anaralkylamino group.

The alkoxycarbonyl group is represented by —COOY′. Examples of Y′ arethe same as the examples of the alkyl group. The alkylamino group andthe aralkylamino group are represented by —NQ¹Q². Examples for each ofQ¹ and Q² are the same as the examples described in relation to thealkyl group and the aralkyl group, and preferable examples for each ofQ¹ and Q² are also the same as those described in relation to the alkylgroup and the aralkyl group. Either one of Q¹ and Q² may be a hydrogenatom.

The arylamino group is represented by —NAr¹Ar². Examples for each of Ar¹and Ar^(e) are the same as the examples described in relation to thenon-fused aromatic hydrocarbon group and the fused aromatic hydrocarbongroup. Either one of Ar¹ and Ar² may be a hydrogen atom.

M represents aluminum (Al), gallium (Ga) or indium (In), among which Inis preferable.

L in the formula (A) represents a group represented by the followingformula (A′) or the following formula (A″).

In the formula (A′), R⁸ to R¹² each independently represent a hydrogenatom or a substituted or unsubstituted hydrocarbon group having 1 to 40carbon atoms. Adjacent groups may form a cyclic structure. In theformula (A″), R¹³ to R²⁷ each independently represent a hydrogen atom ora substituted or unsubstituted hydrocarbon group having 1 to 40 carbonatoms. Adjacent groups may form a cyclic structure.

Examples of the hydrocarbon group having 1 to 40 carbon atomsrepresented by each of R⁸ to R¹² and R¹³ to R²⁷ in the formulae (A′) and(A″) are the same as those of R² to R⁷ in the formula (A).

Examples of a divalent group formed when an adjacent set of R⁸ to R¹²and R¹³ to R²⁷ forms a cyclic structure are a tetramethylene group, apentamethylene group, a hexamethylene group, a diphenylmethane-2,2′-diylgroup, a diphenylethane-3,3′-diyl group, a diphenylpropane-4,4′-diylgroup and the like.

Moreover, in this exemplary embodiment, the electron transporting layermay contain the biscarbazole derivatives represented by the formulae (1)to (3) (or the formulae (4) to (6)).

As an electron transporting compound for the electron injecting layer orthe electron transporting layer, 8-hydroxyquinoline or a metal complexof its derivative, an oxadiazole derivative and a nitrogen-containingheterocyclic derivative are preferable. An example of the8-hydroxyquinoline or the metal complex of its derivative is a metalchelate oxinoid compound containing a chelate of oxine (typically8-quinolinol or 8-hydroxyquinoline). For instance, tris(8-quinolinol)aluminum can be used. Examples of the oxadiazole derivative are asfollows.

In the formula, Ar¹⁷, Ar¹⁸, Ar¹⁹, Ar²¹, Ar²² and Ar²⁵ each represent asubstituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 40 ring carbon atoms. Ar¹⁷, Ar¹⁹and Ar²² may be the same as or different from Ar¹⁸, Ar²¹ and Ar²⁵respectively. Examples of the aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 40 ring carbon atoms are a phenylgroup, biphenyl group, anthranil group, perylenyl group and pyrenylgroup. Examples of the substituent therefor are an alkyl group having 1to 10 carbon atoms, alkoxy group having 1 to 10 carbon atoms and cyanogroup.

Ar²⁰, Ar²³ and Ar²⁴ each represent a substituted or unsubstituteddivalent aromatic hydrocarbon group or fused aromatic hydrocarbon grouphaving 6 to 40 ring carbon atoms. Ar²³ and Ar²⁴ may be mutually the sameor different.

Examples of the divalent aromatic hydrocarbon group or fused aromatichydrocarbon group having 6 to 40 ring carbon atoms are a phenylenegroup, naphthylene group, biphenylene group, anthranylene group,perylenylene group and pyrenylene group. Examples of the substituenttherefor are an alkyl group having 1 to 10 carbon atoms, alkoxy grouphaving 1 to 10 carbon atoms and cyano group.

Such an electron transport compound is preferably an electron transportcompound that can be favorably formed into a thin film(s). Examples ofthe electron transporting compounds are as follows.

An example of the nitrogen-containing heterocyclic derivative as theelectron transporting compound is a nitrogen-containing compound that isnot a metal complex, the derivative being formed of an organic compoundrepresented by one of the following general formulae. Examples of thenitrogen-containing heterocyclic derivative are a five-membered ring orsix-membered ring derivative having a skeleton represented by thefollowing formula (A) and a derivative having a structure represented bythe following formula (B).

In the formula (B), X represents a carbon atom or a nitrogen atom. Z₁and Z₂ each independently represent a group of atoms capable of forminga nitrogen-containing heterocycle.

Preferably, the nitrogen-containing heterocyclic derivative is anorganic compound having a nitrogen-containing aromatic polycyclic grouphaving a five-membered ring or six-membered ring. When thenitrogen-containing heterocyclic derivative includes suchnitrogen-containing aromatic polycyclic series having plural nitrogenatoms, the nitrogen-containing heterocyclic derivative may be anitrogen-containing aromatic polycyclic organic compound having askeleton formed by a combination of the skeletons respectivelyrepresented by the formulae (A) and (B), or by a combination of theskeletons respectively represented by the formulae (A) and (C).

A nitrogen-containing group of the nitrogen-containing aromaticpolycyclic organic compound is selected from nitrogen-containingheterocyclic groups respectively represented by the following generalformulae.

In the formulae: R represents an aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 40 ring carbon atoms; aromaticheterocyclic group or fused aromatic heterocyclic group having 2 to 40ring carbon atoms; alkyl group having 1 to 20 carbon atoms or alkoxygroup having 1 to 20 carbon atoms; and n represents an integer in arange of 0 to 5. When n is an integer of 2 or more, plural R may bemutually the same or different.

A preferable specific compound is a nitrogen-containing heterocyclicderivative represented by the following formula.

HAr-L¹-Ar¹—Ar²

In the formula: HAr represents a substituted or unsubstitutednitrogen-containing heterocyclic group having 1 to 40 ring carbon atoms;L¹ represents a single bond, substituted or unsubstituted aromatichydrocarbon group or fused aromatic hydrocarbon group having 6 to 40ring carbon atoms, or substituted or unsubstituted aromatic heterocyclicgroup or fused aromatic heterocyclic group having 2 to 40 ring carbonatoms; Ar¹ represents a substituted or unsubstituted divalent aromatichydrocarbon group having 6 to 40 ring carbon atoms; and Ar² represents asubstituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 40 ring carbon atoms, orsubstituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 40 ring carbon atoms.

HAr is exemplarily selected from the following group.

L¹ is exemplarily selected from the following group.

Ar¹ is exemplarily selected from the following arylanthranil groups.

In the formulae: R¹ to R¹⁴ each independently represent a hydrogen atom,halogen atom, alkyl group having 1 to 20 carbon atoms, alkoxy grouphaving 1 to 20 carbon atoms, aryloxy group having 6 to 40 ring carbonatoms, substituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 40 ring carbon atoms, or aromaticheterocyclic group or fused aromatic heterocyclic group having 2 to 40ring carbon atoms; and Ar³ represents aromatic hydrocarbon group orfused aromatic hydrocarbon group having 6 to 40 ring carbon atoms, oraromatic heterocyclic group or fused aromatic heterocyclic group having2 to 40 ring carbon atoms.

All of R¹ to R⁸ of a nitrogen-containing heterocyclic derivative may behydrogen atoms.

Ar² is exemplarily selected from the following group.

Other than the above, the following compound (see JP-A-9-3448) can befavorably used for the nitrogen-containing aromatic polycyclic organiccompound as the electron transporting compound.

In the formula: R₁ to R₄ each independently represent a hydrogen atom,substituted or unsubstituted aliphatic group, substituted orunsubstituted alicyclic group, substituted or unsubstituted carbocyclicaromatic cyclic group or substituted or unsubstituted heterocyclicgroup; and X₁ and X₂ each independently represent an oxygen atom, sulfuratom or dicyanomethylene group.

The following compound (see JP-A-2000-173774) can also be favorably usedfor the electron transporting compound.

In the formula, R¹, R², R³ and R⁴, which may be mutually the same ordifferent, each represent an aromatic hydrocarbon group or fusedaromatic hydrocarbon group represented by the following formula.

In the formula, R⁵, R⁶, R⁷, R⁸ and R⁹, which may be mutually the same ordifferent, each represent a hydrogen atom, a saturated or unsaturatedalkoxyl group, alkyl group, amino group or alkylamino group. At leastone of R⁵, R⁶, R⁷, R⁸ and R⁹ represents a saturated or unsaturatedalkoxyl group, alkyl group, amino group or alkylamino group.

A polymer compound containing the nitrogen-containing heterocyclic groupor a nitrogen-containing heterocyclic derivative may be used for theelectron transporting compound.

The electron transporting layer preferably contains at least one ofnitrogen-containing heterocycle derivatives respectively represented bythe following formulae (201) to (203).

In the formulae (201) to (203): R represents a hydrogen atom,substituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 60 ring carbon atoms, substitutedor unsubstituted pyridyl group, substituted or unsubstituted quinolylgroup, substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, or substituted or unsubstituted alkoxy group having 1 to 20carbon atoms;

n is an integer in a range of 0 to 4;

R¹ represents a substituted or unsubstituted aromatic hydrocarbon groupor fused aromatic hydrocarbon group having 6 to 60 ring carbon atoms,substituted or unsubstituted pyridyl group, substituted or unsubstitutedquinolyl group, substituted or unsubstituted alkyl group having 1 to 20carbon atoms, <<nret>> or alkoxy group having 1 to 20 carbon atoms;

R² and R³ each independently represent a hydrogen atom, substituted orunsubstituted aromatic hydrocarbon group or fused aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, substituted or unsubstitutedpyridyl group, substituted or unsubstituted quinolyl group, substitutedor unsubstituted alkyl group having 1 to 20 carbon atoms, or asubstituted or unsubstituted alkoxy group having 1 to 20 carbon atoms;

L represents a substituted or unsubstituted aromatic hydrocarbon groupor fused aromatic hydrocarbon group having 6 to 60 ring carbon atoms,substituted or unsubstituted pyridinylene group, substituted orunsubstituted quinolylene group, or substituted or unsubstitutedfluorenylene group;

Ar¹ represents a substituted or unsubstituted aromatic hydrocarbon groupor fused aromatic hydrocarbon group having 6 to 60 ring carbon atoms,substituted or unsubstituted pyridinylene group, substituted orunsubstituted quinolyl group. Ar^(e) represents a substituted orunsubstituted aromatic hydrocarbon group or fused aromatic hydrocarbongroup having 6 to 60 ring carbon atoms, substituted or unsubstitutedpyridyl group, substituted or unsubstituted quinolyl group, substitutedor unsubstituted alkyl group having 1 to 20 carbon atoms, or substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; and

Ar³ represents a substituted or unsubstituted aromatic hydrocarbon groupor fused aromatic hydrocarbon group having 6 to 60 ring carbon atoms,substituted or unsubstituted pyridyl group, substituted or unsubstitutedquinolyl group, substituted or unsubstituted alkyl group having 1 to 20carbon atoms, substituted or unsubstituted alkoxy group having 1 to 20carbon atoms or group represented by —Ar¹—Ar² (Ar¹ and Ar² may be thesame as the above).

In the formulae (201) to (203), R represents a hydrogen atom, asubstituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 60 ring carbon atoms, substitutedor unsubstituted pyridyl group, substituted or unsubstituted quinolylgroup, substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, or substituted or unsubstituted alkoxy group having 1 to 20carbon atoms.

Although a thickness of the electron injecting layer or the electrontransporting layer is not specifically limited, the thickness ispreferably 1 nm to 100 nm.

The electron injecting layer preferably contains an inorganic compoundsuch as an insulator or a semiconductor in addition to thenitrogen-containing cyclic derivative. Such an insulator or asemiconductor, when contained in the electron injecting layer, caneffectively prevent a current leak, thereby enhancing electroncapability of the electron injecting layer.

As the insulator, it is preferable to use at least one metal compoundselected from the group consisting of an alkali metal chalcogenide, analkali earth metal chalcogenide, a halogenide of alkali metal and ahalogenide of alkali earth metal. By forming the electron injectinglayer from the alkali metal chalcogenide or the like, the electroninjecting capability can preferably be further enhanced. Specifically,preferable examples of the alkali metal chalcogenide are Li₂O, K₂O,Na₂S, Na₂Se and Na₂O, while preferable example of the alkali earth metalchalcogenide are CaO, BaO, SrO, BeO, BaS and CaSe. Preferable examplesof the halogenide of the alkali metal are LiF, NaF, KF, LiCl, KCl andNaCl. Preferable examples of the halogenide of the alkali earth metalare fluorides such as CaF₂, BaF₂, SrF₂, MgF₂ and BeF₂, and halogenidesother than the fluoride.

Examples of the semiconductor are one of or a combination of two or moreof an oxide, a nitride or an oxidized nitride containing at least oneelement selected from Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, Cd, Mg, Si,Ta, Sb and Zn. An inorganic compound for forming the electron injectinglayer is preferably a microcrystalline or amorphous semiconductor film.When the electron injecting layer is formed of such insulator film, moreuniform thin film can be formed, thereby reducing pixel defects such asa dark spot. Examples of such an inorganic compound are theabove-described alkali metal chalcogenide, alkali earth metalchalcogenide, halogenide of the alkali metal and halogenide of thealkali earth metal.

When the electron injecting layer contains such an insulator or such asemiconductor, a thickness thereof is preferably in a range ofapproximately 0.1 nm to 15 nm. The electron injecting layer in thisexemplary embodiment may preferably contain the above-describedreduction-causing dopant.

Hole Injecting Layer and Hole Transporting Layer

The hole injecting layer or the hole transporting layer (including thehole injecting/transporting layer) may contain an aromatic aminecompound such as an aromatic amine derivative represented by thefollowing (I).

In the above (I), Ar¹ to Ar⁴ each represent a substituted orunsubstituted aromatic hydrocarbon group or fused aromatic hydrocarbongroup having 6 to 50 ring carbon atoms, substituted or unsubstitutedaromatic heterocyclic group or fused aromatic heterocyclic group having2 to 40 ring carbon atoms, or a group formed by combining the aromatichydrocarbon group or the fused aromatic hydrocarbon group with thearomatic heterocyclic group or fused aromatic heterocyclic group.

Examples of the compound represented by the formula (I) are shown below.However, the compound represented by the formula (I) is not limitedthereto.

Aromatic amine represented by the following (II) can also be preferablyused for forming the hole injecting layer or the hole transportinglayer.

In the above (II), Ar¹ to Ar³ each represent the same as Ar¹ to Ar⁴ ofthe above (I). Examples of the compound represented by the generalformula (II) are shown below. However, the compound represented by theformula (II) is not limited thereto.

A method of forming each of the layers in the organic EL deviceaccording to this exemplary embodiment is not particularly limited.Conventionally-known methods such as vacuum deposition and spin coatingmay be employed for forming the layers. The organic thin-film layercontaining the compound represented by the formula (1), which is used inthe organic EL device according to this exemplary embodiment, may beformed by a conventional coating method such as vacuum deposition,molecular beam epitaxy (MBE method) and coating methods using a solutionsuch as a dipping, spin coating, casting, bar coating, and roll coating.

Although the thickness of each organic layer of the organic EL deviceaccording to this exemplary embodiment is not particularly limited, thethickness is generally preferably in a range of several nanometers to 1μm because an excessively-thinned film likely entails defects such as apin hole while an excessively-thickened film requires high voltage to beapplied and deteriorates efficiency.

Second Exemplary Embodiment

Next, an organic EL device according to a second exemplary embodimentwill be described below.

The organic EL device according to the second exemplary embodiment isdifferent in that the emitting layer includes the first host material,the second host material and the phosphorescent material. In this case,the first host material is the biscarbazole derivative according to theexemplary embodiment represented by the formulae (1) to (3).

The organic-EL-device material represented by the formulae (1) to (3)has a biscarbazole skeleton having an excellent hole transportingcapability and a heterocyclic skeleton having an excellent electrontransporting capability, which leads to a bi-polar performancesufficient for functioning as a single host. However, a luminousefficiency and a lifetime of the multilayered organic EL device dependon a carrier balance of an entire organic EL device. Main factors forcontrolling the carrier balance are carrier transporting capability ofeach of the organic layers and carrier injecting capability in theinterfacial region of separate organic layers. In order to balance thecarrier injecting capability to neighboring layers in the emitting layer(recombination region), it is preferable to adjust the carrier balancenot by a single host material but by a plurality of host materials.Specifically, it is preferable that, in addition to the first hostmaterial, the second host material is suitably selected as a cohost andused in the emitting layer.

When a material having a poor electron injecting capability (e.g., metalchelate complex) is used as the cathode, a carrier balance in theemitting layer becomes shifted toward the cathode. For improving such adisadvantage, it is preferable to select a material having a highelectron transporting capability as the second host material.Specifically, the host material of this exemplary embodiment ispreferably represented by a formula (5) or (6).

(Cz⁻)_(a)A³  (5)

Cz(⁻A³)_(b)  (6)

In the formula (5) or (6): Cz represents a substituted or unsubstitutedarylcarbazolyl group or carbazolylaryl group;

A³ represents a group represented by a formula (7A) below; and

a and b each represent an integer of 1 to 3.

(M¹)_(c)−(L⁵)_(d)−(M²)_(e)  (7A)

In the formula (7A): M¹ and M² each independently represent asubstituted or unsubstituted nitrogen-containing aromatic heterocyclicring or nitrogen-containing fused aromatic heterocyclic ring having 2 to40 ring carbon atoms; M¹ and M² may be the same or different;

L⁵ represents a single bond, substituted or unsubstituted aromatichydrocarbon group having 6 to 30 carbon atoms, substituted orunsubstituted fused aromatic hydrocarbon group having 6 to 30 carbonatoms, substituted or unsubstituted cycloalkylene group having 5 to 30carbon atoms, substituted or unsubstituted aromatic heterocyclic grouphaving 2 to 30 carbon atoms, or substituted or unsubstituted fusedaromatic heterocyclic group having 2 to 30 carbon atoms;

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

Compounds Represented by Formulae (5) and (6)

Cz is a substituted or unsubstituted arylcarbazolyl group or substitutedor unsubstituted carbazolylaryl group.

An arylcarbazolyl group means a carbazolyl group having at least onearyl group or heteroaryl group as a substituent, in which a positionwhere the aryl group or heteroaryl group is substituted does not matter.

Specific examples are as follows. In the following chemical formulae, Arrepresents an aryl group or heteroaryl group. * represents a positionwhere another group is bonded.

A carbazolylaryl group means an aryl group having at least onecarbazolyl group as a substituent, in which a position where the arylgroup is substituted does not matter.

Specific examples are as follows. In the following chemical formulae, Arrepresents an aryl group. * represents a position where another group isbonded.

A substituted arylcarbazolyl group means the arylcarbazolyl group havingat least one substituent irrespective of a substitution position. Asubstituted carbazolylaryl group means the carbazolylaryl group havingat least one substituent irrespective of a substitution position.

In the formulae (5) and (6), a and b each represent an integer of 1 to3.

An aryl group in the arylcarbazolyl group or carbazolylaryl grouppreferably has 6 to 30 carbon atoms. Examples of the aryl group are aphenyl group, naphthyl group, anthryl group, phenanthryl group,naphthacenyl group, pyrenyl group, fluorenyl group, biphenyl group andterphenyl group, among of which a phenyl group, naphthyl group, biphenylgroup and terphenyl group are preferable.

Examples of the heteroaryl group in the arylcarbazolyl group are groupsformed based on rings of pyridine, pyrimidine, pyrazine, triazine,aziridine, azaindolizine, indolizine, imidazoles, indole, isoindole,indazole, purine, pteridine, d-carboline, naphthyridine, quinoxaline,terpyridine, bipyridine, acridine, phenanthroline, phenazine andimidazopyridine, among which rings of pyridine, terpyridine, pyrimidine,imidazopyridine and triazine are preferable.

A in the formulae (5) and (6) is a group represented by the formula(7A).

In the formula (7A), M¹ and M² each independently represent asubstituted or unsubstituted nitrogen-containing heterocyclic grouphaving 2 to 40 ring carbon atoms. M¹ and M² may be the same ordifferent.

Examples of the nitrogen-containing heterocyclic ring in thearylcarbazolyl group are groups formed based on rings of pyridine,pyrimidine, pyrazine, triazine, aziridine, azaindolizine, indolizine,imidazoles, indole, isoindole, indazole, purine, pteridine, â-carboline,naphthyridine, quinoxaline, terpyridine, bipyridine, acridine,phenanthroline, phenazine and imidazopyridine, among which rings ofpyridine, terpyridine, pyrimidine, imidazopyridine and triazine arepreferable.

L⁵ represents a single bond, substituted or unsubstituted aromatichydrocarbon group or fused aromatic hydrocarbon group having 6 to 30carbon atoms, substituted or unsubstituted cycloalkylene group having 5to 30 carbon atoms, or substituted or unsubstituted aromaticheterocyclic group or fused aromatic heterocyclic group having 2 to 30carbon atoms.

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

Examples of the aromatic hydrocarbon group or fused aromatic hydrocarbongroup having 6 to 30 carbon atoms are a phenyl group, biphenyl group,terphenyl group, naphthyl group, anthranil group, phenanthryl group,pyrenyl group, crycenyl group, fluoranthenyl group and perfluoroarylgroup, fluorenyl group, and 9,9-dimethylfluorenyl group, among which aphenyl group, biphenyl group, terphenyl group and perfluoroaryl groupare preferable.

Examples of the cycloalkylene group having 5 to 30 carbon atoms arecyclopentyl group, cyclohexylene group, and cyclohepthylene group, amongwhich a cyclohexylene group is preferable.

Examples of the aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 30 carbon atoms are 1-pyrrolyl group,2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group,3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group,3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group,7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolylgroup, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group,7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranyl group,3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group,6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group,3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranylgroup, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 2-quinolylgroup, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolylgroup, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group,3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group,6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group,2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group,1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolylgroup, 9-carbazolyl group, 1-phenanthridinyl group, 2-phenanthridinylgroup, 3-phenanthridinyl group, 4-phenanthridinyl group,6-phenanthridinyl group, 7-phenanthridinyl group, 8-phenanthridinylgroup, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinylgroup, 2-acridinyl group, 3-acridinyl group, 4-acridinyl group,9-acridinyl group, 1,7-phenanthrolin-2-yl group, 1,7-phenanthrolin-3-ylgroup, 1,7-phenanthrolin-4-yl group, 1,7-phenanthrolin-5-yl group,1,7-phenanthrolin-6-yl group, 1,7-phenanthrolin-8-yl group,1,7-phenanthrolin-9-yl group, 1,7-phenanthrolin-10-yl group,1,8-phenanthrolin-2-yl group, 1,8-phenanthrolin-3-yl group,1,8-phenanthrolin-4-yl group, 1,8-phenanthrolin-5-yl group,1,8-phenanthrolin-6-yl group, 1,8-phenanthrolin-7-yl group,1,8-phenanthrolin-9-yl group, 1,8-phenanthrolin-10-yl group,1,9-phenanthrolin-2-yl group, 1,9-phenanthrolin-3-yl group,1,9-phenanthrolin-4-yl group, 1,9-phenanthrolin-5-yl group,1,9-phenanthrolin-6-yl group, 1,9-phenanthrolin-7-yl group,1,9-phenanthrolin-8-yl group, 1,9-phenanthrolin-10-yl group,1,10-phenanthrolin-2-yl group, 1,10-phenanthrolin-3-yl group,1,10-phenanthrolin-4-yl group, 1,10-phenanthirolin-5-yl group,2,9-phenanthrolin-1-yl group, 2,9-phenanthrolin-3-yl group,2,9-phenanthrolin-4-yl group, 2,9-phenanthrolin-5-yl group,2,9-phenanthrolin-6-yl group, 2,9-phenanthrolin-7-yl group,2,9-phenanthrolin-8-yl group, 2,9-phenanthrolin-10-yl group,2,8-phenanthrolin-1-yl group, 2,8-phenanthrolin-3-yl group,2,8-phenanthrolin-4-yl group, 2,8-phenanthrolin-5-yl group,2,8-phenanthrolin-6-yl group, 2,8-phenanthrolin-7-yl group,2,8-phenanthrolin-9-yl group, 2,8-phenanthrolin-10-yl group,2,7-phenanthrolin-1-yl group, 2,7-phenanthrolin-3-yl group,2,7-phenanthrolin-4-yl group, 2,7-phenanthrolin-5-yl group,2,7-phenanthrolin-6-yl group, 2,7-phenanthrolin-8-yl group,2,7-phenanthrolin-9-yl group, 2,7-phenanthrolin-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrol-1-yl group, 2-methylpyrrol-3-yl group,2-methylpyrrol-4-yl group, 2-methylpyrrol-5-yl group,3-methylpyrrol-1-yl group, 3-methylpyrrol-2-yl group,3-methylpyrrol-4-yl group, 3-methylpyrrol-5-yl group,2-t-butylpyrrol-4-yl group, 3-(2-phenylpropyl)pyrrol-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group, and4-t-butyl-3-indolyl group, among which a pyridinyl group and quinolylgroup are preferable.

Examples of the substituents for Cz, M¹ and M² in the formulae (5), (6)and (7A) are a halogen atom such as chlorine, bromine and fluorine,carbazole group, hydroxyl group, substituted or unsubstituted aminogroup, nitro group, cyano group, silyl group, trifluoromethyl group,carbonyl group, carboxyl group, substituted or unsubstituted alkylgroup, substituted or unsubstituted alkenyl group, substituted orunsubstituted arylalkyl group, substituted or unsubstituted aromatichydrocarbon group or fused aromatic hydrocarbon group, substituted orunsubstituted aromatic heterocyclic group or fused aromatic heterocyclicgroup, substituted or unsubstituted aralkyl group, substituted orunsubstituted aryloxy group, and substituted or unsubstituted alkyloxygroup. Among these, a fluorine atom, methyl group, perfluorophenylenegroup, phenyl group, naphthyl group, pyridyl group, pyrazil group,pyrimidyl group, adamantyl group, benzyl group, cyano group and silylgroup are preferable.

Bonding patterns of the compound represented by the formula (5) or (6)are shown in Table 1 below in accordance with values of a and b.

TABLE 1 a = b = 1 a = 2 a = 3 b = 2 b = 3 Cz—A³ Cz—A³—Cz

A³—Cz—A³

Bonding patterns of the compound represented by the formula (7A) areshown in Tables 2 and 3 below in accordance with values of c, d and e.

TABLE 2 No c d e Bonding Patterns (1) 0 1 1 L⁵—M² (2) 0 1 2 L⁵—M²—M²,M²—L⁵—M² (3) 0 2 1 L⁵—L⁵—M², L⁵—M²—L⁵ (4) 0 2 2 L⁵—L⁵—M²—M²,M²—L⁵—L⁵—M²,

(5) 1 1 0 the same as [1](M² is replaced with M¹) (6) 1 1 1 M¹—L⁵—M² (7)1 1 2

(8) 1 2 0 the same as [3] (M² is replaced with M¹) (9) 1 2 1M¹—L⁵—L⁵—M², L⁵—M¹—L⁵—M², L⁵—M¹—L⁵—M² (10) 1 2 2 M^(1—)L⁵—L⁵—M²—M²,M²—L⁵—M¹—L⁵—M²,

(11) 2 1 0 the same as [2] (M² is replaced with M¹) (12) 2 1 1 the sameas [7] (M² is replaced with M¹) (13) 2 1 2

TABLE 3 No c d e Bonding Patterns (14) 2 2 0 the same as [4] (M² isreplaced with M¹) (15) 2 2 1 the same as [10] (M² is replaced with M¹)(16) 2 2 2 M¹—M¹—L⁵—L⁵—M²—M²,

Cz bonded to A may be bonded to any one of M¹, L⁵ and M² of the formula(7A) representing A.

For instance, when a=b=1 and Cz-A³-Cz are given in the formula (5) or(6) and [6] (c=d=e=1) of Table 2 is given in the formula (A), threebonding patterns of Cz-M¹-L⁵-M², M¹-L⁵(Cz)-M², and M¹-L⁵-M²-Cz arelisted.

Moreover, for instance, when a=2 and Cz-A³-Cz are given in the formula(5) and [7] (c=d=1,e=2) Table 2 is given in the formula (7A), thefollowing bonding patterns are listed.

In the bonding patterns of the formulae (5), (6) and (7A) and exemplarycombinations of the groups as described above, compounds represented by[1] to [4] below are preferable.

[1] a=1 is given in the formula (5) and c=1 and d=0 are given in theformula (7A).

In the formula (5), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7A): M¹ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁵is a substituted or unsubstituted aryl group or aromatic hydrocarbongroup or fused aromatic hydrocarbon group having 6 to 30 carbon atomsand substituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 30 carbon atoms.

[2] a=2 is given in the formula (5) and c=1 and e=0 are given in theformula (7A).

In the formula (5), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7A): M¹ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁵is a substituted or unsubstituted aryl group or aromatic hydrocarbongroup or fused aromatic hydrocarbon group having 6 to 30 carbon atomsand substituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 30 carbon atoms.

[3] a=1 is given in the formula (5) and c=2 and e=0 are given in theformula (7A).

In the formula (5), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7A): M¹ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁵is a substituted or unsubstituted aryl group or aromatic hydrocarbongroup or fused aromatic hydrocarbon group having 6 to 30 carbon atomsand substituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 30 carbon atoms.

[4] b=2 is given in the formula (6) and c=d=1 is given in the formula(7A).

In the formula (6), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7A): M¹ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁵is a substituted or unsubstituted aryl group or aromatic hydrocarbongroup or fused aromatic hydrocarbon group having 6 to 30 carbon atomsand substituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 30 carbon atoms.

In the formulae (5) and (6), Cz is preferably a substituted orunsubstituted arylcarbazolyl group, more preferably phenylcarbozolylgroup. Moreover, an aryl site of the arylcarbazolyl group is preferablysubstituted by a carbazolyl group.

Specific examples of the compound represented by the formula (5)according to this exemplary embodiment are shown below, but the compoundrepresented by the formula (25) is not limited thereto.

Specific examples of the compound represented by the formula (6) areshown below, but the compound represented by the formula (6) is notlimited thereto.

The compound represented by the formula (5) or (6) in this exemplaryembodiment has triplet energy gap of 2.5 eV to 3.3 eV, preferably 2.5 eVto 3.2 eV.

The compound represented by the formula (5) or (6) in this exemplaryembodiment has singlet energy gap of 2.8 eV to 3.8 eV, preferably 2.9 eVto 3.7 eV.

Third Exemplary Embodiment

An organic EL device according to a third exemplary embodiment isdifferent from the organic EL device according to the second exemplaryembodiment in that a material having a poor electron capability is usedas the second material.

When a material having an excellent electron injecting capability fromthe electrode (e.g., LiF) is used as the cathode, a carrier balance inthe emitting layer becomes shifted toward the anode. For improving sucha disadvantage, it is preferable to select a material having a poorelectron injecting capability as the second host material. Specifically,the second host material of this exemplary embodiment is preferably acompound in which A³ is a group represented by the following formula(7B) in the formula (5) or (6).

(M³)_(c)−(L⁶)_(d)−(M⁴)_(e)  (7B)

In the formula (7B): M³ and M⁴ each independently represent asubstituted or unsubstituted aromatic hydrocarbon group having 6 to 40ring carbon atoms; M³ and M⁴ may be the same or different; L⁶ representsa single bond, substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 carbon atoms, substituted or unsubstituted fused aromatichydrocarbon group having 6 to 30 carbon atoms, or substituted orunsubstituted cycloalkylene group having 5 to 30 carbon atoms;

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

In the formula (7B), as the aromatic hydrocarbon group for M³ and M⁴ andthe aromatic hydrocarbon group, fused aromatic hydrocarbon group andcycloalkylene group for L⁶, those represented by the formula (26A) canbe used. As bonding patterns of the groups represented by the formula(27B), the same bonding patterns as those of the formula (7A) can beused. Specifically, in the bonding patterns of the formula (7A), M¹, L⁵and M² may be respectively replaced with M³, L⁶ and M⁴.

In the bonding patterns of the formulae (5), (6) and (7B) and exemplarycombinations of the groups as described above, compounds represented by[5] to [8] below are preferable.

[5] a=1 is given in the formula (5) and c=1 and d=0 are given in theformula (7B).

In the formula (5), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7B): M³ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁶is a substituted or unsubstituted aryl group or aromatic hydrocarbongroup or fused aromatic hydrocarbon group having 6 to 30 carbon atomsand substituted or unsubstituted aromatic heterocyclic group or fusedaromatic heterocyclic group having 2 to 30 carbon atoms.

[6] a=2 is given in the formula (5) and c=1 and e=0 are given in theformula (7B).

In the formula (5), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7B): M³ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁶is a substituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 30 carbon atoms and substitutedor unsubstituted aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 30 carbon atoms.

[7] a=1 is given in the formula (5) and c=2 and e=0 are given in theformula (7B).

In the formula (5), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7B): M³ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁶is a substituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 30 carbon atoms and substitutedor unsubstituted aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 30 carbon atoms.

[8] b=2 is given in the formula (6) and c=d=1 is given in the formula(7B).

In the formula (6), Cz is a substituted or unsubstituted arylcarbazolylgroup or substituted or unsubstituted carbazolylaryl group.

In the formula (7B): M³ is a substituted or unsubstitutednitrogen-containing six-membered or seven-membered hetero ring having 4to 5 ring carbon atoms, substituted or unsubstituted nitrogen-containingfive-membered hetero ring having 2 to 4 ring carbon atoms, substitutedor unsubstituted nitrogen-containing hetero ring having 8 to 11 ringcarbon atoms, substituted or unsubstituted imidazopyridinyl ring; and L⁶is a substituted or unsubstituted aromatic hydrocarbon group or fusedaromatic hydrocarbon group having 6 to 30 carbon atoms and substitutedor unsubstituted aromatic heterocyclic group or fused aromaticheterocyclic group having 2 to 30 carbon atoms.

In the formulae (5) and (6), Cz is preferably a substituted orunsubstituted arylcarbazolyl group, more preferably phenylcarbozolylgroup. Moreover, an aryl site of the arylcarbazolyl group is preferablysubstituted by a carbazolyl group.

Examples of the compound in which A³ is a group represented by thefollowing formula (7B) in the formula (5) or (6) are listed below.

As the second host material of this exemplary embodiment, a compoundrepresented by a formula (8) below may be used.

In the formula (8): R¹⁰¹ to R¹⁰⁶ each independently represent a hydrogenatom, halogen atom, substituted or unsubstituted alkyl group having 1 to40 carbon atoms, substituted or unsubstituted cycloalkyl group having 3to 15 carbon atoms, substituted or unsubstituted heterocyclic grouphaving 3 to 20 carbon atoms, substituted or unsubstituted alkoxy grouphaving 1 to 40 carbon atoms, substituted or unsubstituted aryl grouphaving 6 to 40 carbon atoms, substituted or unsubstituted aryloxy grouphaving 6 to 20 carbon atoms, substituted or unsubstituted aralkyl grouphaving 7 to 20 carbon atoms, substituted or unsubstituted arylaminogroup having 6 to 40 carbon atoms, substituted or unsubstitutedalkylamino group having 1 to 40 carbon atoms, substituted orunsubstituted aralkylamino group having 7 to 60 carbon atoms,substituted or unsubstituted arylcarbonyl group having 7 to 40 carbonatoms, substituted or unsubstituted arylthio group having 6 to 20 carbonatoms, substituted or unsubstituted halogenated alkyl group having 1 to40 carbon atoms or cyano group;

at least one of R¹⁰¹ to R¹⁰⁶ is a substituted or unsubstituted9-carbazolyl group, substituted or unsubstituted azacarbazolyl grouphaving 2 to 5 nitrogen atoms, or -L-9-carbazolyl group;

L represents a substituted or unsubstituted alkyl group having 1 to 40carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to15 carbon atoms, substituted or unsubstituted heterocyclic group having3 to 20 carbon atoms, substituted or unsubstituted alkoxy group having 1to 40 carbon atoms, substituted or unsubstituted aryl group having 6 to40 carbon atoms, substituted or unsubstituted aryloxy group having 6 to20 carbon atoms, substituted or unsubstituted aralkyl group having 7 to20 carbon atoms, substituted or unsubstituted arylamino group having 6to 40 carbon atoms, substituted or unsubstituted alkylamino group having1 to 40 carbon atoms, substituted or unsubstituted aralkylamino grouphaving 7 to 60 carbon atoms, substituted or unsubstituted arylcarbonylgroup having 7 to 40 carbon atoms, substituted or unsubstituted arylthiogroup having 6 to 20 carbon atoms, or substituted or unsubstitutedhalogenated alkyl group having 1 to 40 carbon atoms;

Xa represents a sulfur atom, oxygen atom or N—R¹⁰⁸; and

R¹⁰⁸ represents the same as R₁₀₁ to R¹⁰⁶.

Specific examples of the substituted or unsubstituted azacarbazolylgroup having 2 to 5 nitrogen atoms are shown below (in which anysubstituent is omitted), but the substituted or unsubstitutedazacarbazolyl group is not limited thereto.

Examples of the halogen atom include fluorine, chlorine, bromine, andiodine.

Examples of the substituted or unsubstituted alkyl group having 1 to 40carbon atoms include a methyl group, an ethyl group, a propyl group, anisopropyl group, an n-butyl group, an s-butyl group, an isobutyl group,a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group,an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecylgroup, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group,an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, ann-octadecyl group, a neopentyl group, a 1-methylpentyl group, a2-methylpentyl group, a 1-pentylhexyl group, a 1-butylpentyl group, a1-heptyloctyl group, a 3-methylpentyl group, a hydroxymethyl group, a1-hydroxyethyl group, a 2-hydroxyethyl group, a 2-hydroxyisobutyl group,a 1,2-dihydroxyethyl group, a 1,3-dihydroxyisopropyl group, a2,3-dihydroxy-t-butyl group, a 1,2,3-trihydroxypropyl group, achloromethyl group, a 1-chloroethyl group, a 2-chloroethyl group, a2-chloroisobutyl group, a 1,2-dichloroethyl group, a1,3-dichloroisopropyl group, a 2,3-dichloro-t-butyl group, a1,2,3-trichloropropyl group, a bromomethyl group, a 1-bromoethyl group,a 2-bromoethyl group, a 2-bromoisobutyl group, a 1,2-dibromoethyl group,a 1,3-dibromoisopropyl group, a 2,3-dibromo-t-butyl group, a1,2,3-tribromopropyl group, an iodomethyl group, a 1-iodoethyl group, a2-iodoethyl group, a 2-iodoisobutyl group, a 1,2-diiodoethyl group, a1,3-diiodoisopropyl group, a 2,3-diiodo-t-butyl group, a1,2,3-triiodopropyl group, an aminomethyl group, a 1-aminoethyl group, a2-aminoethyl group, a 2-aminoisobutyl group, a 1,2-diaminoethyl group, a1,3-diaminoisopropyl group, a 2,3-diamino-t-butyl group, a1,2,3-triaminopropyl group, a cyanomethyl group, a 1-cyanoethyl group, a2-cyanoethyl group, a 2-cyanoisobutyl group, a 1,2-dicyanoethyl group, a1,3-dicyanoisopropyl group, a 2,3-dicyano-t-butyl group, a1,2,3-tricyanopropyl group, a nitromethyl group, a 1-nitroethyl group, a2-nitroethyl group, a 1,2-dinitroethyl group, a 2,3-dinitro-t-butylgroup, and a 1,2,3-trinitropropyl group, among of which a methyl group,an ethyl group, a propyl group, an isopropyl group, an n-butyl group, ans-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, ann-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, ann-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecylgroup, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecylgroup, an n-heptadecyl group, an n-octadecyl group, a neopentyl group, a1-methylpentyl group, a 1-pentylhexyl group, a 1-butylpentyl group, a1-heptyloctyl group are preferable. The alkyl group (excluding asubstituent) preferably has 1 to 10 carbon atoms.

Examples of the substituted or unsubstituted cycloalkyl group having 3to 15 carbon atoms include a cyclopentyl group, cyclohexyl group,cyclooctyl group, and 3,5,5,5-tetramethylcyclohexyl group. A cyclohexylgroup, cyclooctyl group, and 3,5-tetramethylcyclohexyl group arepreferable. The cycloalkyl group (excluding a substituent) preferablyhas 3 to 12 carbon atoms.

Examples of the substituted or unsubstituted heterocyclic group having 3to 20 carbon atoms are a 1-pyroryl group, 2-pyroryl group, 3-pyrorylgroup, pyrazinyl group, 2-pyridinyl group, 1-imidazolyl, 2-imidazolyl,1-pyrazolyl, 1-indolidinyl, 2-indolidinyl, 3-indolidinyl, 5-indolidinyl,6-indolidinyl, 7-indolidinyl, 8-indolidinyl, 2-imidazopyridinyl,3-imidazopyridinyl, 5-imidazopyridinyl, 6-imidazopyridinyl,7-imidazopyridinyl, 8-imidazopyridinyl, 3-pyridinyl group, 4-pyridinylgroup, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group,5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furylgroup, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group,4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolylgroup, azacarbazolyl-1-yl, azacarbazolyl-2-yl, azacarbazolyl-3-yl,azacarbazolyl-4-yl, azacarbazolyl-5-yl, azacarbazolyl-6-yl,azacarbazolyl-7-yl, azacarbazolyl-8-yl, azacarbazolyl-9-yl,1-phenanthrydinyl group, 2-phenanthrydinyl group, 3-phenanthrydinylgroup, 4-phenanthrydinyl group, 6-phenanthrydinyl group,7-phenanthrydinyl group, 8-phenanthrydinyl group, 9-phenanthrydinylgroup, 10-phenanthrydinyl group, 1-acridinyl group, 2-acridinyl group,3-acridinyl group, 4-acridinyl group, 9-acridinyl group,1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group, 1-dibenzofuranyl group, 2-dibenzofuranylgroup, 3-dibenzofuranyl group, 4-dibenzofuranyl group,1-dibenzothiophenyl group, 2-dibenzothiophenyl group,3-dibenzothiophenyl group, 4-dibenzothiophenyl group, 1-silafluorenylgroup, 2-silafluorenyl group, 3-silafluorenyl group, 4-silafluorenylgroup, 1-germafluorenyl group, 2-germafluorenyl group, 3-germafluorenylgroup and 4-germafluorenyl group.

Among the above, the heterocyclic group is preferably a 2-pyridinylgroup, 1-indolidinyl, 2-indolidinyl, 3-indolidinyl, 5-indolidinyl,6-indolidinyl, 7-indolidinyl, 8-indolidinyl, 2-imidazopyridinyl,3-imidazopyridinyl, 5-imidazopyridinyl, 6-imidazopyridinyl,7-imidazopyridinyl, 8-imidazopyridinyl, 3-pyridinyl group, 4-pyridinylgroup, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group,5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 9-carbazolylgroup, 1-dibenzofuranyl group, 2-dibenzofuranyl group, 3-dibenzofuranylgroup, 4-dibenzofuranyl group, 1-dibenzothiophenyl group,2-dibenzothiophenyl group, 3-dibenzothiophenyl group,4-dibenzothiophenyl group, 1-silafluorenyl group, 2-silafluorenyl group,3-silafluorenyl group, 4-silafluorenyl group, 1-germafluorenyl group,2-germafluorenyl group, 3-germafluorenyl group, 4-germafluorenyl group,azacarbazolyl-1-yl group, azacarbazolyl-2-yl group, azacarbazolyl-3-ylgroup, azacarbazolyl-4-yl group, azacarbazolyl-5-yl group,azacarbazolyl-6-yl group, azacarbazolyl-7-yl group, azacarbazolyl-8-ylgroup, and azacarbazolyl-9-yl group. The heterocyclic group (excluding asubstituent) preferably has 3 to 14 carbon atoms.

The substituted or unsubstituted alkoxy group having 1 to 40 carbonatoms is a group represented by —OY. Examples of Y are the same as thosedescribed in relation to the alkyl group. Preferred examples are alsothe same.

Examples of the substituted or unsubstituted aryl group having 6 to 40carbon atoms (including a fused aromatic hydrocarbon group and a ringassembly aromatic hydrocarbon group) are a phenyl group, 2-biphenylylgroup, 3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group,o-cumenyl group, m-cumenyl group, p-cumenyl group, 2,3-xylyl group,3,4-xylyl group, 2,5-xylyl group, mesityl group and m-quarter-phenylgroup. Among the above, the substituted or unsubstituted aryl group ispreferably a phenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, p-tolyl group, 3,4-xylyl group,m-quarter-phenyl-2-yl group, 1-naphtyl group, 2-naphtyl group,1-phenanthrenyl group, 2-phenanthrenyl group, 3-phenanthrenyl group,4-phenanthrenyl group, 9-phenanthrenyl group, 1-triphenylenyl group,2-triphenylenyl group, 3-triphenylenyl group, 4-triphenylenyl group,1-chrysenyl group, 2-chrysenyl group, 3-chrysenyl group, 4-chrysenylgroup, 5-chrysenyl group, and 6-chrysenyl group. The aryl group(excluding a substituent) preferably has 6 to 24 carbon atoms. The arylgroup preferably further includes a 9-carbazolyl group as a substituent.

The substituted or unsubstituted aryloxy group having 6 to 20 carbonatoms is a group represented by —OAr. Examples of Ar are the same asthose described in relation to the aryl group. Preferred examples arealso the same.

Examples of the substituted or unsubstituted aralkyl group having 7 to20 carbon atoms are a benzyl group, 1-phenylethyl group, 2-phenylethylgroup, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butylgroup, á-naphthylmethyl group, 1-á-naphthylethyl group,2-á-naphthylethyl group, 1-á-naphthylisopropyl group,2-á-naphthylisopropyl group, â-naphthylmethyl group, 1-â-naphthylethylgroup, 2-â-naphthylethyl group, 1-â-naphthylisopropyl group,2-â-naphthylisopropyl group, 1-pyrorylmethyl group, 2-(1-pyroryl)ethylgroup, p-methylbenzyl group, m-methylbenzyl group, o-methylbenzyl group,p-chlorobenzyl group, m-chlorobenzyl group, o-chlorobenzyl group,p-bromobenzyl group, m-bromobenzyl group, o-bromobenzyl group,p-iodobenzyl group, m-iodobenzyl group, o-iodobenzyl group,p-hydroxybenzyl group, m-hydroxybenzyl group, o-hydroxybenzyl group,p-aminobenzyl group, m-aminobenzyl group, o-aminobenzyl group,p-nitrobenzyl group, m-nitrobenzyl group, o-nitrobenzyl group,p-cyanobenzyl group, m-cyanobenzyl group, o-cyanobenzyl group,1-hydroxy-2-phenylisopropyl group, 1-chloro-2-phenylisopropyl group andthe like. Among these, preferred are a benzyl group, a p-cyanobenzylgroup, m-cyanobenzyl group, o-cyanobenzyl group, 1-phenylethyl group,2-phenylethyl group, 1-phenylisopropyl group, and 2-phenylisopropylgroup. An alkyl portion of the aralkyl group preferably has 1 to 8carbon atoms. An aryl portion thereof (including heteroaryl) preferablyhas 6 to 18 carbon atoms.

The substituted or unsubstituted arylamino group having 6 to 40 carbonatoms, the substituted or unsubstituted alkylamino group having 1 to 40carbon atoms, and the substituted or unsubstituted aralkylamino grouphaving 7 to 60 carbon atoms each are represented by —NQ¹Q². Examples ofQ¹ and Q² each are independently the same as those described in relationto the alkyl group, aryl group and aralkyl group. Preferred examples arealso the same.

The substituted or unsubstituted arylcarbonyl group having 7 to 40carbon atoms is represented by —COAr². Examples of Ar² are the same asthose described in relation to the aryl group. Preferred examples arealso the same.

The substituted or unsubstituted arylthio group having 6 to 20 carbonatoms is exemplified by a group obtained by replacing an oxygen atom ofthe aryloxy group represented by —OAr with a sulfur atom. Preferredexamples are also the same.

The substituted or unsubstituted halogenated alkyl group having 1 to 40carbon atoms is exemplified by a halogenated alkyl group in which atleast one hydrogen atom of the alkyl group is substituted by a halogenatom. Preferred examples are also the same.

The compound represented by the general formula (8) preferably hastriplet energy gap of 2.2 eV to 3.2 eV. Specific examples of the formula(8) are shown below.

Fourth Exemplary Embodiment

An organic EL device according to a fourth exemplary embodiment isdifferent from the organic EL devices according to the second and thirdexemplary embodiments in being a red phosphorescent device.

The compound according to this exemplary embodiment is not disclosed asa phosphorescent host material of which color is specified. However,since having a high resistance against oxidation and reduction, thecompound is also applicable to a red phosphorescent device. As a redphosphorescent device, a hydrocarbon material, which exhibits a smalltriplet energy and broad

electron clouds compared with a green phosphorescent material, can beused. Although the hydrocarbon material is difficult to be used as agreen phosphorescent material because of its small triplet energy, thehydrocarbon material is highly appropriate as a red phosphorescent hostmaterial because of its high oxidation and reduction. Accordingly, byusing the hydrocarbon material as the second host material, a redphosphorescent device can become highly efficient.

The second host material is preferably a compound selected from thegroup consisting of polycyclic aromatic compounds represented byformulae (9A), (9B) and (9C) below.

Ra—Ar¹⁰¹—Rb  (9A)

Ra—Ar¹⁰¹-Ar¹⁰²—Rb  (9B)

Ra—Ar¹⁰¹—Ar¹⁰²—Ar¹⁰³—Rb  (9C)

In the formulae (9A) to (9C), Ar¹⁰¹, Ar¹⁰², Ar¹⁰³, Ra and Rb represent asubstituted or unsubstituted aryl group having 6 to 60 ring carbonatoms.

Ar¹⁰¹, Ar¹⁰², Ar¹⁰³, Ra and Rb preferably represent a polycyclicaromatic skeleton selected from a substituted or unsubstituted benzenering, substituted or unsubstituted naphthalene ring, substituted orunsubstituted chrysene ring, substituted or unsubstituted fluoranthenering, substituted or unsubstituted phenanthrene ring, substituted orunsubstituted benzophenanthrene ring, substituted or unsubstituteddibenzophenanthrene ring, substituted or unsubstituted triphenylenering, substituted or unsubstituted benzo[a]triphenylene ring,substituted or unsubstituted benzochrysene ring, substituted orunsubstituted benzo[b]fluoranthene ring, substituted or unsubstitutedfluorene ring and substituted or unsubstituted picene ring.

It is further preferable that substituents for Ra and Rb are not arylgroups; and Ar¹⁰¹, Ar¹⁰², Ar¹⁰³, Ra and Rb are not substituted orunsubstituted benzene ring at the same time.

Moreover, in the formulae (9A) to (9C), either one or both of Ra and Rbare preferably selected from the group consisting of a substituted orunsubstituted phenanthrene ring, substituted or unsubstitutedbenzo[c]phenanthrene ring and substituted or unsubstituted fluoranthenering.

The polycyclic aromatic skeleton of the polycyclic aromatic compound maybe substituted.

Examples of the substituent for the polycyclic aromatic skeleton are ahalogen atom, hydroxyl group, substituted or unsubstituted amino group,nitro group, cyano group, substituted or unsubstituted alkyl group,substituted or unsubstituted alkenyl group, substituted or unsubstitutedcycloalkyl group, substituted or unsubstituted alkoxy group, substitutedor unsubstituted aromatic hydrocarbon group, substituted orunsubstituted aromatic heterocyclic group, substituted or unsubstitutedaralkyl group, substituted or unsubstituted aryloxy group, substitutedor unsubstituted alkoxycarbonyl group, and carboxyl group. Preferredexamples of the aromatic hydrocarbon group are naphthalene,phenanthrene, fluorene, chrysene, fluoranthene and triphenylene.

When the polycyclic aromatic skeleton has a plurality of substituents,the substituents may form a ring.

The polycyclic aromatic skeleton is preferably any one selected from thegroup consisting of compounds represented by formulae (9-1) to (9-4)below.

In the formulae (9-1) to (9-4), Ar¹ to Ar⁵ each represent a substitutedor unsubstituted fused ring structure having 4 to 16 ring carbon atoms.

Examples of the compound represented by the formula (9-1) are elementarysubstances or derivatives of substituted or unsubstituted phenanthreneand chrysene.

Examples of the compound represented by the formula (9-2) are elementarysubstances or derivatives of substituted or unsubstitutedacenaphthylene, acenaphthene and fluoranthene.

Examples of the compound represented by the formula (9-3) are elementarysubstances or derivatives of substituted or unsubstitutedbenzofluoranthene.

Examples of the compound represented by the formula (9-4) are elementarysubstances or derivatives of substituted or unsubstitutedbenzofluoranthene.

The naphthalene derivative is exemplified by a formula (9-5) below.

In the formula (9-5), R₁ to R₈ each independently represent a hydrogenatom, or a substituent consisting of one of or a combination of two ormore of substituted or unsubstituted aryl group having 5 to 30 ringcarbon atoms, branched or linear alkyl group having 1 to 30 carbon atomsand substituted or unsubstituted cycloalkyl group having 3 to 20 carbonatoms.

The naphthalene derivative is exemplified by a formula (9-6) below.

In the formula (9-6), R₁ to R₁₀ each independently represent a hydrogenatom, or a substituent consisting of one of or a combination of two ormore of substituted or unsubstituted aryl group having 5 to 30 ringcarbon atoms, branched or linear alkyl group having 1 to 30 carbon atomsand substituted or unsubstituted cycloalkyl group having 3 to 20 carbonatoms.

The chrysene derivative is exemplified by a formula (9-7) below.

In the formula (9-7), R₁ to R₁₂ each independently represent a hydrogenatom, or a substituent consisting of one of or a combination of two ormore of substituted or unsubstituted aryl group having 5 to 30 ringcarbon atoms, branched or linear alkyl group having 1 to 30 carbon atomsand substituted or unsubstituted cycloalkyl group having 3 to 20 carbonatoms.

The polyaromatic skeleton is preferably benzo[c]phenanthrene or itsderivative. The benzo[c]phenanthrene derivative is exemplified by aformula (9-8) below.

In the formula (9-8), R₁ to R₉ each independently represent a hydrogenatom, or a substituent consisting of one of or a combination of two ormore of substituted or unsubstituted aryl group having 5 to 30 ringcarbon atoms, branched or linear alkyl group having 1 to 30 carbon atomsand substituted or unsubstituted cycloalkyl group having 3 to 20 carbonatoms.

The polycyclic aromatic skeleton is preferably benzo[c]chrysene or itsderivative. The benzo[c]phenanthrene derivative is exemplified by aformula (9-9) below.

In the formula (9-9), R₁ to R₁₁ each independently represent a hydrogenatom, or a substituent consisting of one of or a combination of two ormore of substituted or unsubstituted aryl group having 5 to 30 ringcarbon atoms, branched or linear alkyl group having 1 to 30 carbon atomsand substituted or unsubstituted cycloalkyl group having 3 to 20 carbonatoms.

The polycyclic aromatic skeleton is preferably dibenzo[c,g]phenanthrenerepresented by a formula (9-10) below or its derivative.

The polycyclic aromatic skeleton is preferably fluoranthene or itsderivative. The fluoranthene derivative is exemplified by a formula(9-11) below.

In the formula (9-11), X₁₂ to X₂₁ each represent a hydrogen atom;halogen atom; linear, branched or cyclic alkyl group; linear, branchedor cyclic alkoxy group; substituted or unsubstituted aryl group; orsubstituted or unsubstituted heteroaryl group.

The polycyclic aromatic skeleton is preferably triphenylene or itsderivative. The triphenylene derivative is exemplified by a formula(9-12) below.

In the formula (9-12), R₁ to R₆ each independently represent a hydrogenatom, or a substituent consisting of one of or a combination of two ormore of substituted or unsubstituted aryl group having 5 to 30 ringcarbon atoms, branched or linear alkyl group having 1 to 30 carbon atomsand substituted or unsubstituted cycloalkyl group having 3 to 20 carbonatoms.

The polycyclic aromatic compound may be represented by a formula (9-13)below.

In the formula (9-13), Ra and Rb represent the same as Ra and Rb in theformulae (9A) to (9C). When Ra, Rb and the naphthalene ring have asingle or plural substituent(s), the single or plural substituents) arean alkyl group having 1 to 20 carbon atoms, haloalkyl group having 1 to20 carbon atoms, cycloalkyl group having 5 to 18 carbon atoms, silylgroup having 3 to 20 carbon atoms, cyano group or halogen atom, whilesubstituents for the naphthalene rings other than Ra and Rb are furtherallowed to be an aryl group having 6 to 22 carbon atoms.

In the formula (9-13), Ra and Rb each preferably represent a groupselected from fluorene ring, phenanthrene ring, triphenylene ring,benzophenanthrene ring, dibenzophenanthrene ring, benzotriphenylenering, fluoranthene ring, benzochrysene ring, benzo[b]fluoranthene ringand picene ring.

Fifth Exemplary Embodiment

The second host material is preferably a monoamine derivativerepresented by any one of formulae (10) to (12) below.

In the formula (10), Ar¹¹¹, Ar¹¹² and Ar¹¹³ each are a substituted orunsubstituted aryl group or heteroaryl group.

The aryl group has 6 to 50 ring carbon atoms (preferably 6 to 30 ringcarbon atoms, more preferably 6 to 20 ring carbon atoms). Examples ofthe aryl group are a phenyl group, naphthyl group, phenanthrenyl group,benzophenanthrenyl group, dibenzophenanthrenyl group, benzochrysenylgroup, dibenzochrysenyl group, fluoranthenyl group, benzofluoranthenylgroup, triphenylenyl group, benzotriphenylenyl group,dibenzotriphenylenyl group, picenyl group, benzopicenyl group,dibenzopicenyl group, phenalenyl group, acenaphthenyl group, anddiazaphenanthrenyl group. Among the above, a phenyl group or naphthylgroup is preferable.

The heteroaryl group has 5 to 50 ring atoms (preferably 6 to 30 ringatoms, more preferably 6 to 20 ring atoms). Examples of the heteroarylgroup are a pyrimidyl group and diazaphenanthrenyl group.

At least one of Ar¹¹¹, Ar¹¹² and Ar¹¹³ is preferably a fused aromatichydrocarbon group selected from a phenanthrenyl group,benzophenanthrenyl group, dibenzophenanthrenyl group, benzochrysenylgroup, dibenzochrysenyl group, fluoranthenyl group, benzofluoranthenylgroup, triphenylenyl group, benzotriphenylenyl group,dibenzotriphenylenyl group, picenyl group, benzopicenyl group,dibenzopicenyl group, phenalenyl group, and diazaphenanthrenyl group.Among the above, a benzochrysenyl group, triphenylenyl group, orphenanthrenyl group is more preferable. Preferably, the fused aromatichydrocarbon group is unsubstituted.

In the monoamine derivative represented by the formula (10), Ar¹¹¹ andAr¹¹² each are preferably a phenyl group or naphthyl group, and Ar¹¹³ ispreferably a benzochrysenyl group, triphenylenyl group, or phenanthrenylgroup.

In the formula (11), Ar¹¹⁴, Ar¹¹⁵ and Ar¹¹⁷ each are a substituted orunsubstituted aryl group or heteroaryl group.

Examples of the aryl group or heteroaryl group are the same as thosedefined as the aryl group or heteroaryl group for Ar¹¹¹, among which aphenyl group or naphthyl group is preferable.

Ar¹¹⁶ is a substituted or unsubstituted arylene group or heteroarylenegroup.

The arylene group has 6 to 50 ring carbon atoms (preferably 6 to 30 ringcarbon atoms, more preferably 6 to 20 ring carbon atoms). Examples ofthe arylene group are a phenylene group, naphthylene group,phenanthrenylene group, naphthacenylene group, pyrenylene group,biphenylene group, terphenylenylene group, benzophenanthrenylene group,dibenzophenanthrenylene group, benzochrysenylene group,dibenzochrysenylene group, fluoranthenylene group, benzofluoranthenylenegroup, triphenylenylene group, benzotriphenylenylene group,dibenzotriphenylenylene group, picenylene group, benzopicenylene group,and dibenzopicenylene group. Among the above, a phenylene group ornaphthylene group is preferable.

The heteroaryl group has 5 to 50 ring atoms (preferably 6 to 30 ringatoms, more preferably 6 to 20 ring atoms). Examples of the heteroarylgroup are a pyridylene group, pyrimidylene group, dibenzofuranylenegroup, and dibenzothiophenylene group.

Ar¹¹⁷ is preferably a fused aromatic hydrocarbon group selected from aphenanthrenyl group, benzophenanthrenyl group, dibenzophenanthrenylgroup, benzochrysenyl group, dibenzochrysenyl group, fluoranthenylgroup, benzofluoranthenyl group, triphenylenyl group, benzotriphenylenylgroup, dibenzotriphenylenyl group, picenyl group, benzopicenyl group,and dibenzopicenyl group. Among the above, a benzochrysenyl group,triphenylenyl group, or phenanthrenyl group is more preferable.Preferably, the fused aromatic hydrocarbon group is unsubstituted.

In the monoamine derivative of the formula (11), more preferably, Ar¹¹⁴and Ar¹¹⁵ each are a phenyl group or naphthyl group, Ar¹¹⁶ is a phenylgroup or naphthyl group, and Ar¹¹⁷ is a benzochrysenyl group,triphenylenyl group, or phenanthrenyl group.

In the formula (12), Ar¹¹⁸, Ar¹¹⁹ and Ar¹²¹ are a substituted orunsubstituted aryl group or heteroaryl group.

Examples of the aryl group or heteroaryl group are the same as thosedefined as the aryl group or heteroaryl group for Ar¹¹¹ and arepreferably a phenyl group.

Ar¹²⁰ is a substituted or unsubstituted arylene group or heteroarylenegroup and the same as those defined as the arylene group orheteroarylene group for Ar¹¹⁶.

Ar¹²⁰ is preferably a phenylene group or naphthylene group.

n is an integer of 2 to 5, preferably 2 to 4, more preferably 2 to 3.When n is 2 or more, Ar¹²⁰ may be mutually the same or different.

Ar¹²¹ is preferably a fused aromatic hydrocarbon group selected from aphenyl group, naphthyl group, phenanthrenyl group, benzophenanthrenylgroup, dibenzophenanthrenyl group, benzochrysenyl group,dibenzochrysenyl group, fluoranthenyl group, benzofluoranthenyl group,triphenylenyl group, benzotriphenylenyl group, dibenzotriphenylenylgroup, picenyl group, benzopicenyl group, dibenzopicenyl group,phenalenyl group, and diazaphenanthrenyl group. Among the above, abenzochrysenyl group, triphenylenyl group, or phenanthrenyl group ismore preferable.

In the exemplary embodiment, for the second host material in the formula(12), Ar¹¹⁸ and Ar¹¹⁹ each are preferably a phenyl group or naphthylgroup; Ar¹²⁰ is preferably a phenylene group or naphthylene group; andAr¹²¹ is preferably a benzochrysenyl group, triphenylenyl group, orphenanthrenyl group.

When Ar¹⁰¹ to Ar¹²¹ have substituent(s), the substituent(s) ispreferably an alkyl group having 1 to 20 carbon atoms, haloalkyl grouphaving 1 to 20 carbon atoms, cycloalkyl group having 3 to 18 carbonatoms, aryl group having 6 to 30 ring carbon atoms, silyl group having 3to 20 carbon atoms, cyano group, and halogen atom.

Examples of the alkyl group are a methyl group, ethyl group, propylgroup, isopropyl group, n-butyl group, 1-methylpropyl group and1-propylbutyl group.

Examples of the aryl group are the same as those for Ar¹⁰¹.

The haloalkyl group is exemplified by a 2,2,2-trifluoroethyl group.

Examples of the cycloalkyl group are a cyclopropyl group, cyclobutylgroup, cyclopentyl group, cyclohexyl group and cyclooctyl group.

Examples of the silyl group are a trimethylsilyl group and triethylsilylgroup.

Examples of the halogen atom are fluorine, chlorine, bromine, andiodine.

When the monoamine derivatives represented by the formulae (10) to (12)do not have a substituent, it is meant that a hydrogen atom issubstituted. The hydrogen atom of the monoamine derivatives representedby the formulae (10) to (12) includes light hydrogen and deuterium.“Carbon atoms forming a ring (ring carbon atoms)” mean carbon atomsforming a saturated ring, unsaturated ring, or aromatic ring. “Atomsforming a ring (ring atoms)” mean carbon atoms and hetero atoms forminga ring including a saturated ring, unsaturated ring, or aromatic ring.

Specific examples of the monoamine derivatives represented by theformula (10) are shown below.

Specific examples of the monoamine derivatives represented by theformula (11) are shown below.

Specific examples of the monoamine derivatives represented by theformula (12) are shown below.

Sixth Exemplary Embodiment

In an organic EL device according to a sixth exemplary embodiment, anaromatic amine compound is used as the second host material.

An example of the aromatic amine compound is preferably a compoundrepresented by the formula (13) or (14).

In the formula (13): X³ represents a substituted or unsubstitutedarylene group having 10 to 40 ring carbon atoms; and

A³ to A⁶ represent a substituted or unsubstituted aryl group having 6 to60 ring carbon atoms, or heteroaryl group having 6 to 60 ring atoms.

In the formula (14), A⁷ to A⁹ represent a substituted or unsubstitutedaryl group having 6 to 60 ring carbon atoms, or heteroaryl group having6 to 60 ring atoms.

The second host material represented by the formula (13) or (14) ispreferably represented by formulae (15) to (19).

In the formulae (15) to (19): A¹⁰ to A¹⁹ each represent a substituted orunsubstituted aryl group having 6 to 40 carbon atoms, substituted orunsubstituted aromatic heterocyclic group having 2 to 40 carbon atoms,substituted or unsubstituted aryl group having 8 to 40 carbon atomsbonded with an aromatic amino group, or substituted or unsubstitutedaryl group having 8 to 40 carbon atoms bonded with an aromaticheterocyclic group;

A¹⁰, A¹³, A¹⁵ and A¹⁷ are adapted to be respectively bonded to A¹¹, A¹⁴,A¹⁶ and A¹⁸ to form a ring;

X⁴ to X⁹ represent a single bond or a linking group having 1 to 30carbon atoms;

Y⁶ to Y²⁴ represent a hydrogen atom, halogen atom, substituted orunsubstituted alkyl group having 1 to 40 carbon atoms, substituted orunsubstituted heterocyclic group having 3 to 20 carbon atoms,substituted or unsubstituted aryl group having 6 to 40 carbon atoms,substituted or unsubstituted aralkyl group having 7 to 20 carbon atoms,substituted or unsubstituted alkenyl group having 2 to 40 carbon atoms,substituted or unsubstituted alkylamino group having 1 to 40 carbonatoms, substituted or unsubstituted aralkylamino group having 7 to 60carbon atoms, substituted or unsubstituted alkylsilyl group having 3 to20 carbon atoms, substituted or unsubstituted arylsilyl group having 8to 40 carbon atoms, substituted or unsubstituted aralkylsilyl grouphaving 8 to 40 carbon atoms, or substituted or unsubstituted halogenatedalkyl group having 1 to 40 carbon atoms; and

X_(A), X_(B), X_(C), X_(D), X_(E) each represent a sulfur atom, anoxygen atom or a monoaryl-substituted nitrogen atom.

Examples of compounds represented by the formulae (13), (14), and (15)to (19) are as follows.

Seventh Exemplary Embodiment

An organic EL device according to a seventh exemplary embodimentpreferably contains a metal complex as the second host material.

The metal complex is preferably represented by a formula (20) below.

L¹¹L¹²L¹³M¹¹ ₂Q¹¹  (20)

In the formula: ligands L¹¹, L¹² and L¹³ are independently selected froma structure represented by a formula (21) below; M¹¹ is a divalentmetal; and Q¹¹ is a monovalent anion induced from inorganic or organicacids.

In the ligands: Xb is O, S or Se; a-ring is oxazole, thiazole,imidazoles, oxadiazole, thiadiazole, benzooxazole, benzothiazole,benzoimidazole, pyridine, or quinoline; R¹²¹ to R¹²⁴ are independentlyhydrogen, an alkyl group having 1 to 5 carbon atoms, halogen, silylgroup or aryl group having 6 to 20 carbon atoms, which may be bonded toan adjacent substituent via alkylene or alkenylene to form a fused ring.

The pyridine and quinoline may be bonded to R1 to form a fused ring.

The a-ring and the aryl group for R¹²¹ to R¹²⁴ may be furthersubstituted by a C1-C5 alkyl group, halogen, C1-C5 alkyl group having ahalogen substituent, phenyl group, naphthyl group, silyl group, or aminogroup.

The ligands L¹¹, L¹² and L¹³ are independently selected from thefollowing structures.

In the ligands: X and R₁ to R₄ represent the same as Xb and R¹²¹ to R¹²⁴in the formula (21); Y is O, S or NR₂₁; Z is CH or N; R₁₁ to R₁₆ areindependently hydrogen, a C1-C5 alkyl group, halogen, C1-C5 alkyl grouphaving a halogen substituent, phenyl group, naphthyl group, silyl group,or amino group; and R₁₁ to R₁₄ may be bonded to an adjacent substituentvia alkylene or alkenylene to form a fused ring.

The ligands L¹¹, L¹² and L¹³ of the compound may be the same and can beselected from the following structures.

In the ligands: X is O, S or Se; R₂, R₃, R₁₂ and R₁₃ are independentlyhydrogen, methyl, ethyl, n-propyl, isopropyl, fluorine, chlorine,trifluoromethyl, phenyl, naphthyl, fluorenyl, trimethylsilyl,triphenylsilyl, t-butyldimethylsilyl, dimethylamine, diethylamine, ordiphenylamine.

The phenyl, naphthyl, fluorenyl are further substituted by fluorine,chlorine, trimethylsilyl, triphenylsilyl, t-butyldimethylsilyl,dimethylamine, diethylamine, or diphenylamine

Furthermore, in this exemplary embodiment, the metal complex ispreferably a zinc complex. Examples of such a preferable zinc complexare shown below.

Eighth Exemplary Embodiment

The second host material may be compounds represented by formulae (22)to (24) below.

In the formulae (22) to (24): X¹⁰¹ to X¹⁰⁸ are a nitrogen atom orC—Ar¹³¹.

Ar¹³¹ represent a hydrogen atom, a fluorine atom, a cyano group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms,substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms,substituted or unsubstituted haloalkyl group having 1 to 20 carbonatoms, substituted or unsubstituted haloalkoxy group having 1 to 20carbon atoms, substituted or unsubstituted alkylsilyl having 1 to 10carbon atoms, substituted or unsubstituted arylsilyl having 6 to 30carbon atoms, substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, substituted or unsubstituted fusedaromatic hydrocarbon group having 6 to 30 ring carbon atoms, substitutedor unsubstituted aromatic heterocyclic group having 2 to 30 ring carbonatoms, or substituted or unsubstituted fused aromatic heterocyclic grouphaving 2 to 30 ring carbon atoms.

Adjacent ones of X¹⁰¹ to X¹⁰⁸ may be bonded to each other to form a ringstructure.

B¹ and B² represent a group represented by a formula (25A) or (25B)below.

(M¹)_(c)−(L⁵)_(d)−(M²)_(e)  (5)

In the formula (25A): M¹ and M² each independently represent asubstituted or unsubstituted nitrogen-containing aromatic heterocyclicring or nitrogen-containing fused aromatic heterocyclic ring having 2 to40 ring carbon atoms; M¹ and M² may be the same or different;

L⁵ represents a single bond, substituted or unsubstituted aromatichydrocarbon group having 6 to 30 carbon atoms, substituted orunsubstituted fused aromatic hydrocarbon group having 6 to 30 carbonatoms, substituted or unsubstituted cycloalkylene group having 5 to 30carbon atoms, substituted or unsubstituted aromatic heterocyclic grouphaving 2 to 30 carbon atoms, or substituted or unsubstituted fusedaromatic heterocyclic group having 2 to 30 carbon atoms;

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

(M³)_(c)−(L⁶)_(d)−(M⁴)_(e)  (25B)

In the formula (25B): M³ and M⁴ each independently represent asubstituted or unsubstituted aromatic hydrocarbon group having 2 to 40ring carbon atoms; M³ and M⁴ may be the same or different; L⁶ representsa single bond, substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 carbon atoms, substituted or unsubstituted fused aromatichydrocarbon group having 6 to 30 carbon atoms, or substituted orunsubstituted cycloalkylene group having 5 to 30 carbon atoms;

c represents an integer of 0 to 2; d represents an integer of 1 to 2; erepresents an integer of 0 to 2; and c+e represents 1 or more.

The formulae (25A) and (7A) are respectively the same as the formulae(25B) and (7B). M¹ to M⁴ and L⁵ to L⁶ are the same as those described inrelation to the formulae (7A) and (7B).

Specific examples of compounds represented by the formulae (22) to (24)are shown.

Ninth Exemplary Embodiment

The second host material may be compounds represented by the aboveformula (1) and having a different structure from that of the first hostmaterial.

It should be noted that the invention is not limited to the abovedescription but may include any modification as long as suchmodification stays within a scope and a spirit of the invention.

For instance, the following is a preferable example of such modificationmade to the invention.

In the invention, the emitting layer may also preferably contain anassistance material for assisting injection of charges.

When the emitting layer is formed of a host material that exhibits awide energy gap, a difference in ionization potential (Ip) between thehost material and the hole injecting/transporting layer etc. becomes solarge that injection of the holes into the emitting layer becomesdifficult, which may cause a rise in a driving voltage required forproviding sufficient luminance.

In the above instance, introducing a hole-injectable/transportableassistance material for assisting injection of charges in the emittinglayer can contribute to facilitation of the injection of the holes intothe emitting layer and to reduction of the driving voltage.

As the assistance material for assisting the injection of charges, forinstance, a typical hole injecting/transporting material or the like canbe used.

Specific examples of the assistance material for assisting the injectionof charges are a triazole derivative, oxadiazole derivative, imidazolesderivative, polyarylalkane derivative, pyrazoline derivative, pyrazolonederivative, phenylenediamine derivative, arylamine derivative,amino-substituted chalcone derivative, oxazole derivative,styrylanthracene derivative, fluorenone derivative, hydrazonederivative, silazane derivative, polysilane copolymer, anilinecopolymer, and conductive polymer oligomer (particularly, a thiopheneoligomer).

The hole injecting material is exemplified by the above. The holeinjecting material is preferably a porphyrin compound, aromatic tertiaryamine compound and styryl amine compound, particularly preferablyaromatic tertiary amine compound.

In addition, 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl(hereinafter, abbreviated as NPD) having two fused aromatic rings in amolecule, or4,4′,4″-tris(N-(3-methylphenyl)-N-phenylamino)triphenylamine(hereinafter, abbreviated as MTDATA) in which three triphenylamine unitsare bonded in a starburst form as disclosed and the like may also beused.

Moreover, a hexaazatriphenylene derivative and the like may be alsopreferably used as the hole injecting material.

Alternatively, inorganic compounds such as p-type Si and p-type SiC canalso be used as the hole-injecting material.

EXAMPLES

Next, the invention will be described in further detail by exemplifyingExample(s) and Comparison(s). However, the invention is not limited bythe description of Example(s).

Synthesis Example 1 Synthesis of Compound 1

A synthesis scheme is shown below.

Synthesis of Intermediate Body 1-1

4-bromobenzaldehyde (25 g, 135 mmol) and acetophenone (16.2 g, 135 mmol)were added to ethanole (200 mL). An aqueous solution of 3M potassiumhydrate (60 mL) was further added thereto and stirred at roomtemperature for 7 hours. A precipitated solid was separated byfiltration. Then, the obtained solid was washed with methanol. A whitesolid intermediate body 1-1 (28.3 g, a yield rate 73%) was obtained.

Synthesis of Intermediate Body 1-2

The intermediate body 1-1 (20 g, 69.7 mmol) and benzamidinehydrochloride (10.8 g, 69.7 mmol) were added to ethanole (300 mL).Sodium hydroxide (5.6 g, 140 mmol) was further added thereto and heatedto reflux at room temperature for 8 hours. A precipitated solid wasseparated by filtration. Then, the obtained solid was washed withhexane. A white solid intermediate body 1-2 (10.3 g, a yield rate 38%)was obtained.

Synthesis of Intermediate Body 1-3

Carbazole (15 g, 92.6 mmol) was added to ethanol (70 mL). Sulfuric acid(6 mL), water (3 mL), HIO₄.2H₂O (8.2 g, 35.9 mmol) and I₂ (9.1 g, 35.9mmol) were added thereto and stirred at room temperature for 4 hours.Water was added to the reaction solution and a precipitated solid wasseparated by filtration. Then, the obtained solid was washed withmethanol. By dissolving the obtained solid in heated toluene forrecrystallization, an intermediate body 1-3 (5.1 g, a yield rate 18.8%)was obtained.

Synthesis of Intermediate Body 1-4

Under an argon gas atmosphere, N-phenylcarbazolyl-3-boronic acid (2.0 g,7.0 mmol), the intermediate body 1-3 (2.05 g, 7.0 mmol), Pd(PPh₃)₄ (0.15g, 0.14 mmol), toluene (20 mL) and an aqueous solution of 2M sodiumcarbonate (10.5 mL) were added together, and stirred at 80 degrees C.for 7 hours. Water was added to the reaction solution to precipitatesolid. Then, the obtained solid was washed with methanol. By washing theobtained solid by heated toluene, an intermediate body 1-4 (2.43 g, ayield rate 84%) was obtained.

Synthesis of Compound 1

Under an argon gas atmosphere, to a three-necked flask, the intermediatebody 1-2 (2.28 g, 5.88 mmol), the intermediate body 1-4 (2.4 g, 5.88mmol), CuI (0.56 g, 2.9 mmol), tripotassium phosphate (2.5 g, 11.8mmol), anhydrous dioxane (30 mL) and cyclohexane diamine (0.33 g, 2.9mmol) were added together in sequential order, and stirred at 100degrees C. for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was refined by silica-gel column chromatography, wherebya white solid compound 1 (2.7 g, a yield rate 65%) was obtained.

FD-MS analysis consequently showed that m/e was equal to 714 while acalculated molecular weight was 714.

Synthesis Example 2 Synthesis of Compound 2

The intermediate body 1-1 (6.49 g, 22.6 mmol), phenacylpyridiniumbromide (12.7 g, 45.6 mmol), ammonium acetate (45 g), acetic acid (200mL), and N,N-dimethylformamide (200 mL) were heated to reflux andstirred for 8 hours.

The reaction solution was put into an ice water and a precipitated solidwas separated by filtration. Then, the obtained solid was washed withmethanol. The obtained solid was refined by silica-gel columnchromatography (dissolving solvent: hexane/methylene chloride), wherebyan intermediate body 2-1 (3.7 g, a yield rate 42%) was obtained.

Subsequently, under an argon gas atmosphere, to a three-necked flask,the intermediate body 2-1 (2.81 g, 7.3 mmol), the intermediate body 1-4(3.0 g, 7.3 mmol), Cut (1.4 g, 7.3 mmol), tripotassium phosphate (2.3 g,11 mmol), anhydrous dioxane (30 mL) and cyclohexane diamine (0.84 g, 7.3mmol) were added together in sequential order, and stirred at 100degrees C. for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was refined by silica-gel column chromatography, wherebya compound 2 (3.4 g, a yield rate 65%) was obtained.

FD-MS analysis consequently showed that m/e was equal to 713 while acalculated molecular weight was 713.

A synthesis scheme of the compound 2 is shown below.

Synthesis Example 3 Synthesis of Compound 3

Under a nitrogen gas atmosphere, trichloropyrimidine (8 g, 43.4 mmol),phenylboronic acid (11.6 g, 95.4 mmol),tetrakis(triphenylphosphine)palladium (1.83 g, 1.74 mmol), toluene (300mL) and an aqueous solution of 2M sodium carbonate (130 mL) were addedtogether in sequential order, and heated to reflux for 8 hours. Afterthe reaction solution was cooled down to the room temperature, anorganic layer was removed and an organic solvent was distilled awayunder reduced pressure. The obtained residue was refined by silica-gelcolumn chromatography, whereby an intermediate body 3-1 (8.2 g, a yieldof 71%) was obtained.

Subsequently, under a nitrogen gas atmosphere, intermediate body 3-1 (8g, 29.9 mmol), p-chlorophenylboronic acid (5.1 g, 32.9 mmol),tetrakis(triphenylphosphine)palladium (0.63 g, 0.6 mmol), toluene (60mL) and an aqueous solution of 2M sodium carbonate (30 mL) were addedtogether in sequential order, and heated to reflux for 8 hours.

After the reaction solution was cooled down to the room temperature, anorganic layer was removed and an organic solvent was distilled awayunder reduced pressure. The obtained residue was refined by silica-gelcolumn chromatography, whereby an intermediate body 3-2 (7.0 g, a yieldof 68%) was obtained.

Under an argon gas atmosphere, the intermediate body 3-2 (6.5 g, 18.9mmol), the intermediate body 1-4 (7.7 g, 18.9 mmol), palladium acetate(0.085 g, 0.38 mmol), sodium t-butoxide (2.72 g, 28.4 mmol), anhydroustoluene (60 mL), and tri-t-butyl phosphine (0.077 g, 0.38 mmol) weresequentially mixed, and stirred at 90 degrees C. for 8 hours.

After the reaction solution was cooled down to the room temperature, anorganic layer was removed and an organic solvent was distilled awayunder reduced pressure. The obtained residue was refined by silica-gelcolumn chromatography, whereby a compound 3 (7.8 g, a yield of 58%) wasobtained.

FD-MS analysis consequently showed that m/e was equal to 715 while acalculated molecular weight was 715.

A synthesis scheme of the compound 3 is shown below.

Synthesis Example 4 Synthesis of Compound 4

3,3′-dicarbazolyl was synthesized by a method disclosed in WO2006-25186.

Under an argon gas atmosphere, to a three-necked flask,3,3′-dicarbazolyl (2.4 g, 7.3 mmol), the intermediate body 1-2 (5.6 g,14.6 mmol), Cut (1.4 g, 7.3 mmol), tripotassium phosphate (6.4 g, 30mmol), anhydrous dioxane (50 mL) and cyclohexane diamine (0.84 g, 7.3mmol) were added together in sequential order, and stirred at 100degrees C. for 8 hours.

Water was added to the reaction solution to precipitate solid. Then, theobtained solid was washed with hexane, followed by methanol. Theobtained solid was refined by silica-gel column chromatography, wherebya compound 4 (3.1 g, a yield rate 45%) was obtained.

FD-MS analysis consequently showed that m/e was equal to 945 while acalculated molecular weight was 945.

A synthesis scheme of the compound 4 is shown below.

Synthesis Example 5 Synthesis of Compound 5

Under an argon gas atmosphere, the intermediate body 3-1 (1.0 g, 3.9mmol), the intermediate body 1-4 (1.6 g, 3.9 mmol),tris(dibenzylideneacetone)dipalladium (0.071 g, 0.078 mmol),tri-t-butylphosphonium tetrafluoroborate (0.091 g, 0.31 mmol), sodiumt-butoxide (0.53 g, 5.5 mmol), and anhydrous toluene (20 mL) weresequentially mixed, and heated to reflux for 8 hours.

After the reaction solution was cooled down to the room temperature, anorganic layer was removed and an organic solvent was distilled awayunder reduced pressure. The obtained residue was refined by silica-gelcolumn chromatography, whereby a compound 5 (1.8 g, a yield of 74%) wasobtained.

FD-MS analysis consequently showed that m/e was equal to 639 while acalculated molecular weight was 639.

A synthesis scheme of the compound 5 is shown below.

Synthesis Example 6 Synthesis of Compound 6

3-bromobenzaldehyde (18.4 g, 100 mmol) was dissolved indimethylformamide (300 mL). Benzamidine hydrochloride (31.2 g, 200 mmol)and potassium carbonate (41 g, 300 mmol) were added thereto and heatedto reflux at 80 degrees C. for 8 hours. After the reaction solution wascooled down to the room temperature, an organic layer was removed and anorganic solvent was distilled away under reduced pressure. The obtainedresidue was refined by silica-gel column chromatography, whereby anintermediate body 6-1 (12 g, a yield of 32%) was obtained.

Under an argon gas atmosphere, the intermediate body 6-1 (1.5 g, 3.9mmol), the intermediate body 1-4 (1.6 g, 3.9 mmol),tris(dibenzylideneacetone)dipalladium (0.071 g, 0.078 mmol),tri-t-butylphosphonium tetrafluoroborate (0.091 g, 0.31 mmol), sodiumt-butoxide (0.53 g, 5.5 mmol), and anhydrous toluene (20 mL) weresequentially mixed, and heated to reflux for 8 hours.

After the reaction solution was cooled down to the room temperature, anorganic layer was removed and an organic solvent was distilled awayunder reduced pressure. The obtained residue was refined by silica-gelcolumn chromatography, whereby a compound 6 (2.3 g, a yield of 82%) wasobtained.

FD-MS analysis consequently showed that m/e was equal to 715 while acalculated molecular weight was 715.

A synthesis scheme of the compound 6 is shown below.

Synthesis Example 7 Synthesis of Compound 7

For synthesis of Compound 7, an intermediate body 7-1 was firstlysynthesized by applying a method described in a document (J. Bergman, A.Brynolf, B. Elman and E. Vuorinen, Tetrahedron, 42, 3697-3706(1986)).Specifically, to a three-necked flask (500 ml), 1M tetrahydrofuransolution of phenylmagnesium bromide (100 ml, 100 mmol) was added. Dryether (100 ml) was further added and heated to reflux in an oil bath at45 degrees C. A dry ether solution (50 ml) of 2-cyanoaniline (5.91 g, 50mmol) was dropped in for 30 minutes After refluxed for another 1.5hours, the reaction solution was cooled down to 0 degree C. in an icewater bath. Subsequently, a dry ether solution (100 ml) of4-bromobenzoate chloride (13.2 g, 60 mmol) was dropped in the reactionsolution for 10 minutes and heated to reflux for 2 hours in a45-degree-C oil bath. After reaction, the reaction solution was cooleddown to 0 degree C. in an ice water bath. A saturated ammonium chlorideaqueous solution was added. A precipitated solid was separated byfiltration. Then, the obtained was washed with a small amount ofmethanol and vacuum-dried to obtain an intermediate body 7-1 (10.8 g, ayield of 60%).

Subsequently, under a nitrogen atmosphere, the intermediate body 7-1(1.4 g, 3.9 mmol), the intermediate body 1-4 (1.6 g, 3.9 mmol),tris(dibenzylideneacetone)dipalladium (0.071 g, 0.078 mmol),tri-t-butylphosphonium tetrafluoroborate (0.091 g, 0.31 mmol), sodiumt-butoxide (0.53 g, 5.5 mmol), and anhydrous toluene (20 mL) weresequentially mixed, and heated to reflux for 8 hours. After the reactionsolution was cooled down to the room temperature, an organic layer wasremoved and an organic solvent was distilled away under reducedpressure. The obtained residue was refined by silica-gel columnchromatography, whereby a compound 7 (2.0 g, a yield of 75%) wasobtained.

FD-MS analysis consequently showed that m/e was equal to 688 while acalculated molecular weight was 688.

A synthesis scheme of the compound 7 is shown below.

Synthesis Example 8 Synthesis of Compound 8

Specifically, to a three-necked flask (500 ml), 1M tetrahydrofuransolution of phenylmagnesium bromide (100 ml, 100 mmol) was added. Dryether (100 ml) was further added and heated to reflux in an oil bath at45 degrees C. A dry ether solution (50 ml) of 2-cyanoaniline (5.91 g, 50mmol) was dropped in for 30 minutes After refluxed for another 1.5hours, the reaction solution was cooled down to 0 degree C. in an icewater bath. Subsequently, a dry ether solution (100 ml) of3-bromobenzoate chloride (13.2 g, 60 mmol) was dropped in the reactionsolution for 10 minutes and heated to reflux for 2 hours in a45-degree-C oil bath. After reaction, the reaction solution was cooleddown to 0 degree C. in an ice water bath. A saturated ammonium chlorideaqueous solution was added. A precipitated solid was separated byfiltration. Then, the obtained was washed with a small amount ofmethanol and vacuum-dried to obtain an intermediate body 8-1 (8.5 g, ayield of 47%).

Subsequently, under a nitrogen atmosphere, the intermediate body 8-1(1.4 g, 3.9 mmol), the intermediate body 1-4 (1.6 g, 3.9 mmol),tris(dibenzylideneacetone)dipalladium (0.071 g, 0.078 mmol),tri-t-butylphosphonium tetrafluoroborate (0.091 g, 0.31 mmol), sodiumt-butoxide (0.53 g, 5.5 mmol), and anhydrous toluene (20 mL) weresequentially mixed, and heated to reflux for 8 hours. After the reactionsolution was cooled down to the room temperature, an organic layer wasremoved and an organic solvent was distilled away under reducedpressure. The obtained residue was refined by silica-gel columnchromatography, whereby a compound 8 (1.9 g, a yield of 71%) wasobtained.

FD-MS analysis consequently showed that m/e was equal to 688 while acalculated molecular weight was 688.

A synthesis scheme of the compound 8 is shown below.

Example 1 Manufacture of Organic EL Device

A glass substrate (size: 25 mm×75 mm×1.1 mm) having an ITO transparentelectrode (manufactured by GEOMATEC Co., Ltd.) was ultrasonic-cleaned inisopropyl alcohol for five minutes, and then UV(Ultraviolet)/ozone-cleaned for 30 minutes.

After the glass substrate having the transparent electrode was cleaned,the glass substrate was mounted on a substrate holder of a vacuumdeposition apparatus, and a hole injecting layer was initially formed bydepositing a compound A onto the substrate to be 40 nm thick to cover asurface of the glass substrate where a transparent electrode line wasprovided. Next, a compound B was deposited onto the hole injecting layerto be 20 nm thick, and a hole transporting layer was obtained.

A phosphorescent-emitting layer was obtained by co-depositing thecompound 1 used as a phosphorescent host material and Ir(Ph-ppy)₃ usedas a phosphorescent dopant material onto the hole transporting layer tobe 40 nm thick. The concentration of Ir(Ph-ppy)₃ was 20 mass %.

Subsequently, a 30-nm-thick compound C, 1-nm-thick LiF and 80-nm-thickmetal Al are sequentially layered to obtain a cathode. LiF, which is anelectron injectable electrode, was formed at a speed of 1 Å/min.

Examples 2 to 6 Manufacture of Organic EL Devices 2 to 6

In Example 1, the compounds 2 to 6 below were used in place of thecompound 1 to manufacture organic EL devices 2 to 6.

Comparisons 1 to 4

The organic EL devices according respectively to Comparisons 1 to 4 wereformed in the same manner as in Example 1 except that the followingcomparative compounds D to G were respectively used as a host materialin place of the compound 1 in Example 1.

Evaluation of Organic EL Device

The organic EL devices manufactured in Examples 1 to 6 and Comparisons 1to 4 were driven by direct-current electricity to emit light, whereluminescent performance was evaluated and time elapsed until an initialluminescence intensity of 20,000 cd/m² was reduced to the half wasmeasured. The results are shown in Table 4.

TABLE 4 Luminous Efficiency Voltage (V) (cd/A) @1 Luminance HostMaterial @1 mA/cm² mA/cm² half-life (hrs) Example 1 Compound 1 4.0 61950 Example 2 Compound 2 4.1 63 750 Example 3 Compound 3 4.0 65 730Example 4 Compound 4 4.3 62 670 Example 5 Compound 5 4.1 61 1100 Example6 Compound 6 4.3 64 1000 Comparison 1 Compound D 4.2 38 310 Comparison 2Compound E 4.5 54 450 Comparison 3 Compound F 5.1 50 210 Comparison 4Compound G 4.6 48 350

Table 4 shows that the compounds of the invention used in Examples 1 to6 have a significantly long luminance half-life and a high luminousefficiency while being capable of low-voltage drive compared with thoseof Comparisons 1 to 4.

In Comparison 1, since the compound D has a single carbazolyl group andis poor in hole transporting performance, luminance half-life is short.In Comparison 2, although having two carbazolyl groups, the compound Ehas a poor hole transporting performance and a short luminancehalf-life, presumably because of small overlapping margin between themolecules. In Comparison 3, since the compound F has anitrogen-containing heterocyclic ring only in a carbazolyl group,electrons are difficult to be injected, so that the compound F has a lowluminous efficiency and a short luminance half-life. In Comparison 4,although having two carbazolyl groups, the compound G has a poor holetransporting capability and a short luminance half-life, presumablybecause of small overlapping margin between the molecules.

Example 7 Manufacture of Organic EL Device 7

A glass substrate (size: 25 mm×75 mm×1.1 mm thick) having an ITOtransparent electrode (manufactured by GEOMATEC Co., Ltd.) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes.

After the glass substrate having the transparent electrode line wascleaned, the glass substrate was mounted on a substrate holder of avacuum deposition apparatus, so that the following electron acceptingcompound (C-1) was deposited to form a 5-nm thick C-1 film on a surfaceof the glass substrate where the transparent electrode line was providedso as to cover the transparent electrode. On the C-1 film, the followingaromatic amine derivative (X1) was deposited as a first holetransporting material to form a 50-nm thick first hole transportinglayer. After film formation of the first hole transporting layer, thefollowing aromatic amine derivative (X2) was deposited as a second holetransporting material to form a 60-nm thick second hole transportinglayer.

Further on the second hole transporting layer, the compound 1 obtainedin Synthesis Example 1 was deposited to form a 45-nm thick emittinglayer. Simultaneously, the following compound (D3) was co-deposited as aphosphorescent material. A concentration of the compound D3 was 8.0 mass%. This co-deposited film serves as the emitting layer.

After the film formation of the emitting layer, a 30-nm thick film ofthe following compound (ET2) was formed. The ET1 film serves as theelectron transporting layer.

Next, a 1-nm thick film of LiF was formed as an electron-injectingelectrode (cathode) at a film-forming speed of 0.1 A/min. Metal (Al) wasdeposited on the LiF film to form an 80-nm thick metal cathode, therebyproviding an organic electroluminescence device.

For each of the obtained organic EL devices, luminous efficiency wasmeasured when the device was driven by DC constant current at theinitial luminescence of 2000 cd/m² at the room temperature, and the timeelapsed until a half-life of emission was measured when the device wasdriven by DC constant current at the initial luminescence of 5000 cd/m²at the room temperature. The results are shown in Table 5.

Examples 8 to 14 Manufacture of Organic EL Devices 8 to 14

The organic EL devices according to Examples 8 to 14 were manufacturedin the same manner as that in Example 7 except that the compounds 2 to 8were used in place of the compound 1 as materials for the emittinglayer. For each of the obtained organic EL devices, luminous efficiencywas measured when the device was driven by DC constant current at theinitial luminescence of 2000 cd/m² at the room temperature, and the timeelapsed until a half-life of emission was measured when the device wasdriven by DC constant current at the initial luminescence of 5000 cd/m²at the room temperature. The results are shown in Table 5.

Comparisons 5 and 6

The organic EL devices according to Comparisons 5 and 7 weremanufactured in the same manner as that in Example 7 except that thecomparative compounds D and F were used in place of the compound 1 asmaterials for the emitting layer. For each of the obtained organic ELdevices, luminous efficiency was measured when the device was driven byDC constant current at the initial luminescence of 2000 cd/m² at theroom temperature, and the time elapsed until a half-life of emission wasmeasured when the device was driven by DC constant current at theinitial luminescence of 5000 cd/m² at the room temperature. The resultsare shown in Table 5.

TABLE 5 Luminous Efficiency Luminance Host Material Voltage (V) (cd/A)half-life (hrs) Example 7 Compound 1 4.1 11 400 Example 8 Compound 2 4.310 350 Example 9 Compound 3 4.2 12 540 Example 10 Compound 4 4.4 12 350Example 11 Compound 5 4.1 12 450 Example 12 Compound 6 4.2 12 450Example 13 Compound 7 4.2 11 400 Example 14 Compound 8 4.1 10 350Comparison 5 Compound D 4.1 7 200 Comparison 6 Compound F 5.2 6.5 220

The table 5 shows that the compounds of the invention also function as ared phosphorescent host material.

Examples 15 to 18 and Comparison 7

The organic EL devices according respectively to Examples 15 to 18 andComparison 7 were formed in the same manner as in Example 1 except thatthe materials, a thickness of each of the layers and a concentration ofeach of the emitting materials were changed as shown in Table 6. InTable 6, figures in parentheses without a unit indicate a thickness ofeach of the layers (unit: nm). A structure of HT-7 is shown below.

Table 7 shows physical properties of the host materials used in Examples15 to 18 and Comparison 7.

A method for measuring each of the physical properties is as follows.

(1) Ionization Potential (Ip)

Ionization potential was measured in the atmosphere by using aphotoelectron spectrometer (AC-1 manufactured by Riken Keiki Co., Ltd.).Specifically, ionization potential was measured by irradiating thematerials with light and measuring the amount of electrons generated bycharge separation at that time.

(2) Affinity (Af)

Affinity was calculated based on measurement values of ionizationpotential Ip and energy gap Eg. A calculation equitation is as follows.

Af=Ip−Eg

The energy gap was measured from an absorption end of absorptionspectrum of benzene. Specifically, the absorption spectrum is measuredwith a commercially available ultraviolet-visible spectrophotometer, andthe energy gap is calculated from a wavelength at which the absorptionspectrum appears.

(3) Singlet Energy (S1) and Triplet Energy (T1)

The optical energy gap S1 (also referred to as singlet energy) is adifference between a conduction level and a valence level. The opticalenergy gap was obtained by converting into energy a wavelength value atan intersection of a long-wavelength-side tangent line in an absorbingspectrum of a toluene-diluted solution of each material and a base linein the absorbing spectrum (zero absorption).

The triplet energy gap T1 of the material may be exemplarily definedbased on the phosphorescence spectrum. The triplet energy gap T1 wasdefined as follows in Examples.

Specifically, each material was dissolved in an EPA solvent(diethylether:isopentane:ethanol=5:5:2 in volume ratio) with aconcentration of 10 μmol/L, thereby forming a sample for phosphorescencemeasurement.

Then, the sample for phosphorescence measurement was put into a quartzcell, cooled to 77K and irradiated with exciting light, so that awavelength of phosphorescence radiated therefrom was measured.

A tangent line is drawn to be tangent to a rising section adjacent toshort-wavelength of the obtained phosphorescence spectrum, a wavelengthvalue at an intersection of the tangent line and a base line isconverted into energy value, and the converted energy value is definedas the triplet energy gap T1.

For the measurement, a measurement machine F-4500 (manufactured byHitachi) was used.

Evaluation of Organic EL Device

Voltage was applied to the organic EL device so that a current densitybecomes 10 mA/cm², and a voltage value (V) at that time was measured.Moreover, current efficiency (L/J) (cd/A), power efficiency (lm/W) andlife-time (hrs) were measured.

As for life-time, after the device was driven by constant current at theinitial luminescence, an elapsed time when the luminescence reached 90%of the initial luminescence (LT90) or the luminescence reached 50% ofthe initial luminescence (LT50) was measured.

The results are shown in Table 8.

TABLE 6 Arrangement of Organic EL Device Example 15 ITO(70)/CompoundA(30)/HT-7(20)/PH1 + Ir(ppy)₃(40, 90% + 10%)/ET2(30)/Liq(1)/Al(80)Example 16 ITO(70)/Compound A(30)/HT-7(20)/PH2 + Ir(ppy)₃(40, 90% +10%)/ET2(30)/LiF(1)/Al(80) Example 17 ITO(70)/CompoundA(30)/HT-7(20)/PH3 + Ir(ppy)₃(40, 90% + 10%)/ET2(30)/LiF(1)/Al(80)Example 18 ITO(130)/Compound A(50)/PH2 + Ir(piq)₃(30, 92% +8%)/ET2(30)/LiF(1)/Al(80) Comparison 7 ITO(70)/CompoundA(30)/HT-7(20)/PH5 + Ir(ppy)₃(40, 90% + 10%)/ET2(30)/Liq(1)/Al(80)

TABLE 7 Host Material Ip(eV) Af(eV) S1(eV) T1(eV) PH1

5.5 2.4 3.1 2.9 PH2

5.7 2.3 3.3 2.8 PH3

5.7 2.7 3.0 2.8 PH5

6.1 2.6 3.5 2.7

TABLE 8 Current Host Voltage density luminescence material (V) (mA/cm²)(nit) L/J (cd/A) η (lm/W) LT90 (hrs) LT50 (hrs) Example 15 PH1 3.00 1494 49.4 51.7 250 — @3000 cd/m² Example 16 PH2 2.85 1 637 63.7 70.3 —500 @10000 cd/m² Example 17 PH3 2.67 1 572 57.2 67.3 — 800 @10000 cd/m²Example 18 PH2 3.54 1 85 8.5 7.5 — 1000 @10000 cd/m² Comparison 7 PH52.72 1 492 49.2 56.7 90 — @3000 cd/m²

Example 19 Manufacture of Organic EL Device 19

A glass substrate (size: 25 mm×75 mm×1.1 mm) having an ITO transparentelectrode (manufactured by GEOMATEC Co., Ltd.) was ultrasonic-cleaned inisopropyl alcohol for five minutes, and then UV(Ultraviolet)/ozone-cleaned for 30 minutes.

After the glass substrate having the transparent electrode was cleaned,the glass substrate was mounted on a substrate holder of a vacuumdeposition apparatus, and a hole injecting layer was initially formed bydepositing a compound A onto the substrate to be 40 nm thick to cover asurface of the glass substrate where a transparent electrode line wasprovided. Next, a compound B was deposited onto the hole injecting layerto be 20 nm thick, and a hole transporting layer was obtained.

A phosphorescent-emitting layer was obtained by co-depositing thecompound 3 used as the first phosphorescent host material, Ir(Ph-ppy)₃used as a phosphorescent dopant material, and HT-5 used as the followingsecond host material onto the hole transporting layer to be 40 nm thick.The concentration of Ir(Ph-ppy)₃ was 20 mass % and the concentration ofHT-5 was 10 mass %.

Subsequently, a 30-nm-thick compound C, 1-nm-thick LiF and 80-nm-thickmetal Al are sequentially layered to obtain a cathode. LiF, which is anelectron injectable electrode, was formed at a speed of 1 Å/min.

With respect to the organic EL devices 19, luminescent performance wasevaluated in the same manner as in Example 1 and time elapsed until aninitial luminescence intensity of 20,000 cd/m² was reduced to the halfwas measured. The results are shown in Table 9.

Example 20 Manufacture of Organic EL Device 20

In Example 19, HT-9 was used in place of HT-5 to manufacture an organicEL device 6.

With respect to the organic EL devices 20, luminescent performance wasevaluated in the same manner as in Example 1 and time elapsed until aninitial luminescence intensity of 20,000 cd/m² was reduced to the halfwas measured. The results are shown in Table 9.

Comparison 8

In Example 19, the compound D was used in place of the compound 3 tomanufacture an organic EL device. With respect to the organic ELdevices, luminescent performance was evaluated in the same manner as inExample 1 and time elapsed until an initial luminescence intensity of20,000 cd/m² was reduced to the half was measured. The results are shownin Table 9.

Comparison 9

In Comparison 8, HT-9 was used in place of HT-5 to manufacture anorganic EL device. With respect to the organic EL devices, luminescentperformance was evaluated in the same manner as in Example 1 and timeelapsed until an initial luminescence intensity of 20,000 cd/m² wasreduced to the half was measured. The results are shown in Table 9.

TABLE 9 Voltage Luminous (V) Efficiency First/Second @1 mA/ (cd/A)Luminance host materials cm² @1 mA/cm² half-life (hrs) Example 19Compound 3.9 72 800 3/HT-5 Example 20 Compound 3.9 69 800 3/HT-9Comparison 8 Compound 4.0 40 400 D/HT-5 Comparison 9 Compound 4.1 41 380D/HT-9

Table 9 shows that the compounds of the invention used in Examples 19and 20 have a significantly long luminance half-life and a significantlyhigh luminous efficiency as compared with those in Comparisons 8 and 9.

Examples 21 to 26

The organic EL devices according respectively to Examples 21 to 26 wereformed in the same manner as in Example 19 except that the materials, athickness of each of the layers and a concentration of each of theemitting materials were changed as shown in Table 10.

Table 7 above and Table 11 below show the chemical formulae and physicalproperties of the host material used in Examples 21 to 26.

TABLE 10 Arrangement of Organic EL Device Example 21 ITO(70)/CompoundA(30)/HT-7(20)/PH1 + PH5 + Ir(ppy)₃(40, 45% + 45% +10%)/ET2(30)/Liq(1)/Al(80) Example 22 ITO(70)/CompoundA(30)/HT-7(20)/PH2 + PH6 + Ir(ppy)₃(40, 45% + 45% +10%)/ET2(30)/LiF(1)/Al(80) Example 23 ITO(70)/CompoundA(30)/HT-7(20)/PH3 + PH6 + Ir(ppy)₃(40, 45% + 45% +10%)/ET2(30)/LiF(1)/Al(80) Example 24 ITO(70)/CompoundA(30)/HT-7(20)/PH3 + PH7 + Ir(ppy)₃(40, 45% + 45% +10%)/ET2(30)/LiF(1)/Al(80) Example 25 ITO(130)/Compound A(50)/PH2 +PH10 + Ir(piq)₃(30, 50% + 42% + 8%)/ET2(30)/LiF(1)/Al(80) Example 26ITO(70)/Compound A(30)/HT-7(20)/PH1 + PH3 + Ir(ppy)₃(40, 45% + 45% +10%)/ET2(30)/LiF(1)/Al(80)

TABLE 11 Host Material Ip(eV) Af(eV) S1(eV) T1(eV) PH6 

6.0 2.5 3.5 3.0 PH7 

6.0 2.5 3.5 2.8 PH10

6.2 3.1 3.1 2.3

Evaluation of Organic EL Device

The organic EL devices according to Examples 21 to 26 were evaluated inthe same manner as in Examples 15 to 18. The results are shown in Table12.

FIG. 2(A) shows an energy diagram in the emitting layer in Example 21.FIG. 2(B) shows an energy diagram in the emitting layer in Example 23.

TABLE 12 Current Host Voltage density luminescence material (V) (mA/cm²)(nit) L/J (cd/A) η (lm/W) LT90 (hrs) LT50 (hrs) Example 21 PH1/PH5 2.831 517 51.7 57.5 600 — @3000 cd/m² Example 22 PH2/PH6 3.39 1 673 67.362.4 — 900 @10000 cd/m² Example 23 PH3/PH6 3.10 1 726 72.6 73.6 — 1000@10000 cd/m² Example 24 PH3/PH7 3.08 1 888 88.8 90.6 40 — @20000 cd/m²Example 25 PH2/PH10 3.88 1 92 9.2 7.4 — 1500 @10000 cd/m² Example 26PH2/PH3 2.92 1 752 75.2 80.9 — 750 @10000 cd/m³

In comparison between Table 8 and Table 12, it has been found that theorganic EL devices according to Examples 21 to 26, in which the firstand second host materials are used, have a long life-time and improvedluminous efficiency as compared with the organic EL devices in which asingle host material is used.

1-27. (canceled)
 28. A compound represented by a formula (1) below:

wherein A¹ and A² each mutually independently represent a substituted orunsubstituted aromatic hydrocarbon group having 6 to 30 ring carbonatoms, or a substituted or unsubstituted nitrogen-containingheterocyclic group having 1 to 30 ring carbon atoms, X¹ and X² are eacha linking group and independently represent a single bond, a substitutedor unsubstituted aromatic hydrocarbon group having 6 to 30 ring carbonatoms, a substituted or unsubstituted fused aromatic hydrocarbon grouphaving 10 to 30 ring carbon atoms, a substituted or unsubstitutedaromatic heterocyclic group having 2 to 30 ring carbon atoms, or asubstituted or unsubstituted fused aromatic heterocyclic group having 2to 30 ring carbon atoms, Y¹, Y², Y³ and Y⁴ each independently representa hydrogen atom, a fluorine atom, a cyano group, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted haloalkyl group having 1 to 20 carbon atoms, a substitutedor unsubstituted haloalkoxy group having 1 to 20 carbon atoms, asubstituted or unsubstituted alkylsilyl group having 1 to 10 carbonatoms, a substituted or unsubstituted arylsilyl group having 6 to 30carbon atoms, a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 30 ring carbon atoms, a substituted or unsubstituted fusedaromatic hydrocarbon group having 10 to 30 ring carbon atoms, asubstituted or unsubstituted aromatic heterocyclic group having 2 to 30ring carbon atoms; or a substituted or unsubstituted fused aromaticheterocyclic group having 2 to 30 ring carbon atoms, p and q represent 0or 2, p and q being not simultaneously 0; r and s represent an integerof 1 to 3, when p=2, a plurality of Y¹ may be mutually the same ordifferent, when q=2, a plurality of Y² may be mutually the same ordifferent, when r=2 or 3, a plurality of Y³ may be mutually the same ordifferent, when s=2 or 3, a plurality of Y⁴ may be mutually the same ordifferent, when p is 2, a single pair of adjacent ones of Y¹ aremutually bonded to form a ring structure, and when q is 2, a single pairof adjacent ones of Y² are mutually bonded to form a ring structure. 29.The compound according to claim 28, wherein the ring structure formed bythe mutually bonded adjacent ones of Y¹ when p is 2, and the ringstructure formed by the mutually bonded adjacent ones of Y² when q is 2are represented by any one of formulae (1a), (1b) and (1c) below.


30. The compound according to claim 29, wherein the compound isrepresented by a formula (1-A), (1-B), (1-C), (1-D), (1-E) or (1-F).


31. The compound according to claim 30, wherein A¹ is a substituted orunsubstituted nitrogen-containing compound having 1 to 30 ring carbonatoms.
 32. The compound according to claim 28, wherein one of A¹ and A²is a substituted or unsubstituted pyridine ring, a substituted orunsubstituted pyrimidine ring, a substituted or unsubstituted triazinering, or a substituted or unsubstituted quinazoline ring.
 33. Anorganic-EL-device material comprising the compound according to claim28.
 34. An organic electroluminescence device, comprising: a cathode; ananode; and a plurality of organic thin-film layers comprising anemitting layer, at least one layer of the organic thin-film layerscomprising the organic-EL-device material according to claim
 33. 35. Theorganic electroluminescence device according to claim 34, wherein theemitting layer comprises the organic-EL-device material as a hostmaterial.
 36. The organic electroluminescence device according to claim34, wherein the emitting layer comprises a phosphorescent material. 37.The organic electroluminescence device according to claim 34, whereinthe phosphorescent material is an ortho-metalated complex of a metalatom selected from iridium (Ir), osmium (Os) and platinum (Pt).